At the age of twenty-four, Anna was considered by many as too old to be a baby-sitter. It was true in a way, it had been years since she last spent her time watching someone else's kids to earn a bit of cash. She wasn't doing it for the money however, unlike when she was just a teenager. She was doing it to help a friend.

Her friend Sophie, who was a hard-working single mom, didn't trust the average teenager with her baby son, so she had called in the help of Anna. Sophie was a manager at a large company and spent long hours at the office. At night however, she liked going out to parties and raves and pretending she wasn't yet in her thirties. That had changed of course, when her little boy was born.

Sophie didn't resent her son the lost nights, she had chosen to become a mother after all, her beautiful baby boy the result of donated sperm and many trips to the fertilization clinic. She'd given up her night-life for him, but with the help of Anna, once a week, she could go out and dance away the stress of a demanding job and young child at home.

Anna didn't agree with all of her friend's ideas. She thought it ridiculous that Sophie didn't want a teenager looking after her son, she'd never gotten into any trouble baby-sitting while she was just a teen herself. Yet she knew Sophie wouldn't listen to her opinion on the matter. They used to work at the same company and even then she'd known Sophie to be a strong, opinionated woman. Anna had left the company a while ago, before Sophie had worked her way up to the manager position; but she'd always known her friend would build a great career.

The fact was, Anna loved to look after the little boy. She was looking forward to having her own children some day, but unlike Sophie she didn't feel ready yet to start on her own family. Younger than her friend, she felt she still had time.

Once a week, Anna spent her time with Sophie's baby son. They played a game or read a book, she fed him and gave him his bath and then took him to bed. He wasn't a lot of work, not at this age, and Anna spent most of her time reading or watching TV while listening to his content snoring on the baby-monitor.

Those nights would've been even easier, if Sophie hadn't been such a strict, controlling mother. She'd given Anna very specific instructions: what to feed him, which books to read, the exact time he should be in bed, everything was planned out in excruciating detail. Anna often thought it was a good thing her friend hadn't entrusted the boy to some teenage baby-sitter, for they would surely ignore half of what his mother had said. Sophie's fastidiousness was what helped her build a strong career however, so Anna did her best to follow all of the rules Sophie had set.

It was on one of these nights, when Anna was waiting in Sophie's living room for her friend to return home, that she woke up to someone calling her name.

"Were you sleeping?" Sophie asked, still standing in the doorway.

Anna blinked repeatedly. She groggily looked up at her friend who now entered her apartment and closed the door behind her before taking off her jacket. When realization struck of where she was, Anna immediately turned to the baby-monitor. A soft, content snoring came through, everything was fine.

"How can you be sleeping?" Sophie asked as she approached Anna, hands on her hips. "You should be keeping an eye on the baby!"

Anna pushed herself up to sit straight on the couch where she'd nestled herself, the book she'd been reading had dropped to the floor. She blushed slightly, she hadn't intended to fall asleep. "I'm sorry." She mumbled while reaching for her purse, looking for her phone.

"I can't believe this." Sophie continued, searching for words to convey her displeasure.

Anna fumbled through her purse, somehow believing that finding her phone would make this situation right. Her friend towered above her and her strict eyes and dominant stance called up half-forgotten memories of naughty fantasies a younger version of Anna had once had, in which a naughty baby-sitter might get in trouble with a strict dad and have her bottom turned red at his hand.

Then she found her phone, and she was right, it did turn the situation to her favor. She ignored her friend's strict looks as she stared at the bright screen. "Sophie." She said. "It's three a.m. it's the middle of the night."

Sophie did not respond right away, an awkward silence stretched before she finally replied. "I guess, I'm a bit later than usual."

Anna shook her head. "No wonder I fell asleep." She continued. "You're supposed to be home by twelve, that's the deal."

"Alright, alright." Sophie replied. "I'll try to be home on time next time, but you shouldn't fall asleep while you're looking after the baby."

Anna would've accepted that promise, if her friend hadn't followed it up with that last accusation. Now however, she'd had enough of it. She'd been baby-sitting for Sophie for over two months now and as far as she could remember, she'd never been home by twelve, like they'd agreed upon. She was always late, maybe half-an-hour or a whole hour, though never as late as today. "It's not alright, Sophie." She said. "The baby is sleeping, we should all be sleeping, but you're never back on time."

Her friend blushed, she'd gone from accusing Anna, to now being the one who had to apologize. "I'm sorry." She said. "I'll be home by twelve from now on."

Anna shook her head, it didn't bother her that much if her friend was a little bit late. What bothered her was how she'd reacted to her falling asleep while it was obviously her own fault. "What about barging in here and yelling at me for falling asleep?" She asked.

"I didn't yell." Sophie reacted.

"No? It seemed to me like you did." Anna replied. "So you're not going to apologize before I put you across my knee and teach you some respect?"

Sophie blushed deeply. "You're going to do what?"

Anna felt a blush creep up in her own cheeks. Had she really just said that? The fantasies that had invaded her thoughts earlier must've still been hiding in the back of her mind. Yet she knew, if she backed down now, her dominant, successful friend would turn the conversation to her favor. "Put you across my knee and turn your bottom red until you're ready to apologize." She told her friend.

The words felt ridiculous as she said them, surely she couldn't spank her friend, this wasn't one of her naughty fantasies. Yet Sophie didn't laugh at her threat, instead she stepped back from her, hands behind her back as if she was protecting her bottom. "You wouldn't." She said. "You can't."

Anna licked her lips. A threat was only good if you were willing to go through with it, she knew. Though all Sophie needed to do was apologize and spare them both the embarrassment of going through with this. "I can and I will." She replied.

Sophie didn't look like she wanted to apologize however. "What if I don't let you?" She asked defiantly.

Anna stood up from the couch, hands on hips, she was tired. "I don't know, Sophie." She replied. "Go home, I guess."

Her friend blushed. "Would you come back next week if I promise I won't be late again."

Anna shook her head. "Of course I'll come back, I love your little guy." She didn't really want to spank her friend, did she? She just wanted an apology. Thinking she wouldn't get one however, she turned to leave, walking towards the front door.

"Wait." Sophie suddenly whispered, grabbing her arm. "I'm sorry I yelled."

Anna turned around, smiling as she looked at her friend. She hugged her tightly, it's alright, I know you were just worried."

Sophie blushed as Anna held her at arm's length, hands on her shoulder. "Perhaps I do deserve a spanking." She said.

Anna giggled. "Please forget I said that." She replied. "I don't know where that thought came from."

"I'm serious." Sophie replied. "This isn't the first time I'm home late, I always make you wait, I can't believe you never said something sooner."

Anna grinned. "That's true."

"Doesn't that bother you?" Her friend asked.

"A bit." Anna admitted. "I do feel annoyed every time you're late again."

"Then you should do it." Sophie replied. "Punish me."

Anna blushed, being reminded of how annoyed she was every night, waiting for Sophie to come home, did kindle a desire to punish her friend. Something clicked in her head. "Alright, come over here." She said, returning to the couch and sitting down.

Sophie licked her lips as she stood beside her friend, hands behind her back again, protecting her backside.

"Get across my knee." Anna ordered.

Sophie blushed and knelt on the couch, lowering herself across her friend's lap.

Anna looked down hesitantly at her friend's body as she felt her weight settle across her lap. She and Sophie had met at work and she'd always known her friend to wear professional-looking formal outfits. The first time she'd come baby-sitting and seen her in a short, sparkly dress like tonight had been quite a surprise. Now that short dress was riding up her backside as her friend arched her back, demonstrating how short it really was by revealing the bottom crease of her buttocks.

Anna placed her hand on her friend's backside, the delicate party-dress did nothing to conceal her soft and voluptuous bottom beneath the touch of her hand. She reached down and grabbed the hem of her dress, pulling it up to bare her friend's bottom.

Sophie gasped as her buttocks popped out of her dress and revealed she was wearing nothing underneath. Anna grinned as she discovered her friend went out partying like this. "I never knew how much of a party-girl you really were." She said.

Sophie blushed but did not reply.

Anna placed her hand on her friend's bare buttocks. She wondered what it would be like to be in her friend's place, remembering her old fantasies. Nervous, and full of anticipation, she imagined. Eagerly waiting for her punishment to start. She raised her hand.

The echoing sound of her hand connecting with Sophie's bottom seemed loud in the apartment. Anna glanced at the baby-monitor, but there was no sign that the noise would wake the baby. She raised her hand again.

Anna watched with fascination how Sophie's bottom bounced from the impact of her hand, how the flesh rippled like water when something was dropped in it. Most of all however, it felt good to spank her friend. Again and again her hand came down on her backside and with each stroke she felt better, knowing she deserved this. She thought of every night that Sophie had made her wait past the agreed upon hour and with every memory she increased the strength behind her arm.

Sophie moaned and squirmed as Anna built up her punishment, the sting in her backside quickly growing. Yet the sounds of her discomfort did not bother Anna, in fact they encouraged her to go even harder. She wanted to hear her friend squeal for every night she'd arrived home late.

When her arm grew tired, Anna paused for a moment. She stroked her friend's backside, gently massaging the sensitive pink skin. Again she was reminded of her own fantasies and wondered what it would be like if her bottom was this hot and stinging. She wondered whether this spanking aroused her friend, like she was sure it would've aroused her. To distract herself from those thoughts, she raised her arm again and continued her friend's punishment.

Sophie squirmed and whimpered as Anna's hand rained down on her backside, yet she did not complain or protest, but chose to accept her punishment.

Anna peppered her friend's bottom, its color growing from pink to red, her buttocks bouncing beneath the impact of her hand. She knew it must hurt, for her own hand was stinging fiercely. Yet her friend's silence - other than grunts and moans - encouraged her to continue. If Sophie wasn't ready to apologize or at least plead for her punishment to end, then she obviously deserved all the pain she got.

When Anna finally did pause again, more so to rest her arm than to offer Sophie any respite, she wondered how much her friend wanted this punishment. As she gently massaged her friend's backside, she thought about spanking and punishments like this as it was often portrayed in the media, of rich successful businessmen who secretly visited a dominatrix to take a break from their responsibilities and hectic lives. Was this something Sophie wanted? To not be in control for once, to submit to someone else?

"Is this what you wanted?" Anna asked, dragging her nails across the sore, sensitive skin of Sophie's bottom to grab her attention.

Sophie gasped at the sudden pain. "Yes." She whispered.

Anna blushed slightly, that yes had come from somewhere deep. Her friend's heavy breathing suddenly reminded her of the other option, that her willingness to accept this punishment wasn't born from a desire to submit, but a rather more sexual inclination. "Why?" She asked.

Sophie moaned softly. "I felt bad." She replied. "For yelling at you, for always being late."

Anna slid her hand down her friend's leg. Perhaps it wasn't arousal after all, but she had to make sure. She pulled Sophie's legs apart, he friend didn't even put up any resistance. She forced herself to look at her most private parts, Sophie's exposed pussy, it was swollen and glistening wet. There was no mistake, her friend was deeply turned on by her punishment.

Anna wasn't sure what to do now. She knew that if she was in Sophie's place, if she was the one getting her bottom spanked, she would be just as turned on, just as aroused. Those fantasies were what had gotten them in this situation in the first place. Yet that wasn't what was supposed to happen, this was supposed to be a punishment.

She noticed then, peeking from under the couch, a pair of slippers and she knew what she had to do. She had to make sure Sophie knew this was a serious punishment, so she bent over and grabbed one of the slippers. It was pink, with soft fluffy fur, but a firm, flexible leather sole. She placed it across her friend's backside.

"Wait, what are you doing?" Sophie asked.

"Making sure you won't forget this lesson." Anna replied and she raised her arm once again.

"Wait, stop!" Sophie cried, but the slipper already came down, landing with a loud crack across her backside.

"Why?" Anna asked. "You just told me this is what you wanted." She raised the slipper again.

Sophie squealed as it landed with a crack across her bottom. "No, not like this, this hurts." She protested.

Anna paused for a second, not wanting to take things too far, resting the slipper on her friend's bottom. "It's supposed to hurt." She said. "Or do you not feel bad anymore?"

Sophie was blushing. "I do." She said.

"Don't you deserve to be spanked anymore?" Anna asked.

"I do." Sophie whispered.

"Well then, should I continue?" Anna asked.

Sophie hesitated for a second. "Yes, please."

Anna raised the slipper and it rained down on her friend's backside.

Sophie squealed and kicked her legs, grunting, moaning, squirming, but there was no escape. Again and again the slipper connected with her sore red buttocks, which quickly turned bright red, glowing fiercely hot.

Each squeal, each kick of her friend's legs gave Anna a jolt of gratification, pleasure at seeing her friend's discomfort. It was not a feeling of revenge, for what her friend had done to annoy her, it was a more primal feeling, being in control. It surprised her how much she enjoyed it, how much it turned her on to be the one dealing out the punishment rather than receiving it like she'd so often fantasized about.

She also knew, that despite her squeals and cries, that part of her friend, deep down was still aroused by her punishment, that the loss of control and the growing pain were in fact increasing her arousal, rather than diminishing it. She knew this, because that's what she would feel if she were in her place, if it was her bottom being chastised by this slipper. Safe in this knowledge, Anna continued her friend's punishment despite her cries of pain, her pleading promises and the begging that eventually followed.

When she finally stopped, Sophie was out of breath, weezing as she lay across Anna's lap. Her bottom was on fire, her buttocks swollen and bright red. Even the gentle touch of Anna's hand as she stroked her backside made her flinch.

"Did you learn your lesson?" Anna asked.

"Yes." Sophie whispered.

"And are you now ready to apologize?" She asked.

Sophie had in fact already apologized, over and over again as the slipper landed across her bottom, alternating apologies, pleas and promises. "I'm sorry." She'd said. "I won't yell at you again, I will be home on time." She'd promised. "I'm sorry. Please stop, I'll make it up to you. I'll do anything to make it better."

Those apologies, made in the heat of the moment didn't count however. "I'm sorry." Sophie said, one last time. "For yelling at you and for being late."

Anna paused for a moment, her hand resting on her friend's bottom. The apology sounded genuine and yet she was sure the whole experience had also been an arousing ordeal for her friend. Perhaps she had been right before, thinking this was something her friend needed, a moment to submit, to not be in control for one evening. Something she might want more often. Perhaps it could be both. "From now on you'll be home on time." She said. "At twelve o'clock, like we agreed upon."

"I will." Sophie replied.

"If you're late, and I don't care if it's three hours like today, or just five minutes, we will repeat this lesson." Anna said. "Do you agree?"

Sophie blushed. "I agree." She whispered.

"What do you agree to?" Anna asked, wanting to hear her friend say it.

"I agree to be spanked when I come home late again." Her friend replied.

Anna smiled, part of her was already looking forward to next week, she knew there was no way Sophie would keep her promise. She never got home on time. They both knew it. "You can get up now." She said.

Sophie got up, pulling down her dress over her sore red bottom. She blushed as she looked at her friend. "See you next week?" She asked.

Anna smiled. "Yes, though we can hang out any time you want." She replied. They used to spend a lot of time together, though much less now that Sophie was a mother.

"Sure." Her friend replied. "We could go to the park sometime, my little boy loves to go outside."

Anna nodded. "Yes, hit me up when you're going out and I'll join you guys." She grinned. "Just make sure you're on time."

Sophie blushed. There was no such thing as 'on time' when you were a single mom. "I'll do my best." She promised.

Anna took a deep breath after Sophie closed the door behind her, when she'd finally left. She could hardly believe what had happened tonight. She was still surprised at how much she had enjoyed punishing her friend, it was so different from her usual fantasies where she was the one on the receiving end of such discipline.

Part of her was jealous of Sophie, she realized. She had a pair of slippers at home however, similar to the one she'd used on her friend's backside. It was very late, too late for a good night's rest, she might as well spent a bit more time to deal with the arousal that had built up inside her this evening. A bit more time to apply that slipper to her own backside.