This happened less than a year ago, when we all attended a wedding of a family member.

I have a great relationship with my girlfriend,  we do fun stuff, have fun times and love eachother. The only bad thing is our sex life. She doesnt want me to leave and opened the relationship for me. We have a few simple rules as "No sex in our house" and "Dont ask, Dont tell". This because i am pretty gifted with a 5.8" girthy cock. Though i try everything to make it comfortable like good foreplay, loads of lube, going slow and let her make the move, she just doesnt enjoy.

She talked about it with her sister, to get it off her chest and since then her sister is trying to tease with subtle comments here and there. This sister is the youngest of 3 and the chubbiest, but has a pretty and cute face, a good set of tits and one of the best ass ive ever seen.

A good few months went by with the necessary teasing from her side, her wearing different clothes then im used to see her in and commenting on my bulge a few times when nobody was around.

The week of the wedding she even said "Clint, i'll enjoy seeing you in a nice suit, better try and hide that bulge of yours, or i will have a hard time not looking" and i just couldnt take it anymore and said "Well, you should try and make it hard for me to hide my bulge" and she looked at me and said "Oh, i will make it hard..."

On the wedding day, me and my gf drove to the venue where we met the others. We all gave eachother a few formal kisses on the cheek. But my SIL did something extra. She was dressed in a tight baby blue dress with high heels, her ass looked amazing and the tight dress made her boobs gigantic and her curves stand out.

During these formal kisses, she actually put her hand on my bulge and caressed it, making my cock starting to grow a lil bit. I was looking around to see if anybody was looking, but nobody looked weird.

"Well, i'm going to do my make-up, see you guys later" she said and walked off. I had enough and started to look for the room she got in to do the rest of her make-up. When i found the room, i opened the door and saw her sitting infront of the mirror. She noticed me and said "Look, im sorry, i shouldnt have done that" but i said nothing, closed the door and locked it.

When she heard the lock, she looked at me with this face saying "Oh god, i'm not ready for this" and "Oh yes! I want it so bad!"

The moment she got up, i stood behind her. Grabbed her arms and locked them in a hug, my raging boner gently pressing into her ass. I could see her face in the mirror and her lips read "Oh my god".

I kissed her neck and groped her boobs. She let out a cute moan. She smelled so good! And i started to get a bit rougher.

I put my hands all over her body and eventually lifted her dress to finally get a good grope of her delicious ass. She grabbed one of my hands and leads it to the front and shoved it inside her panties. It was completely hairless and easily found my way to her clit which i started to rub gently, it was like a poolslide there. She let out a "please, i have waited too long for this" and some real cute moans, i rubbed a little faster before she said "please please, stop, you're making me cum too soon" and i stopped.

" i want it so bad!" And lifts her dress, drops her panty and bents over the table, arms fully stretched to grab the edge of the table. She still had no idea what was coming. I dropped my pants, took down my boxers and there it was, my raging 5.8 inch girthy cock.

With one hand i spread her buttcheeks and with the other i put the head of my cock against her pussy opening. She felt that and said "oh my!!". The more i pushed, the more moans came outta this woman. When i only got the tip in, she moaned "Jezus, i feel full already!", she got so wet feeling my cock that the rest went in easier. When it got in she gasped for air and said "god, i feel everything!! It is too big"

I could finally go my way, but went slow with thrusting. My SIL let out some great primal moans and enjoyed the whole thing, but when my thrusts got rougher she started to feel sore. "Okay, i cant handle it anymore" she said while letting out a few gasps of air and moans, and started puffing like she was giving birth... puff puff with every thrust..

puff "please..." puff "please cum.." puff puff "please cum quick" puff moan puff "you're too much"

And after a few more hard thrusts that slapped my balls on her pussylips, i came hard and gave her a nice creampie and payback for teasing me for months. I was still inside her, no thrusting and i started to rub her clit. Seconds later she started to moan hard and i saw her hands grip the table harder. I felt her pussy pulsating on my cock and a hard long moan came out of her while she was cumming.

While i was cleaning myself, she was still trying to regain and just lay there on the table. Cum dripping out her, i got her up, gave her panty back, she cleaned herself and i straightened her dress.

"Now lets enjoy the rest of the day" i said and she just smiled at me and said "i'll probably just sit at the bar drinking i guess" walking like she already had too many drinks and we still had to attend the ceremony.

Later that week i got a text from her saying "i dont regret letting you have me, but there wont be a second time!"

Fun fact... i came a second time, in her.