This all started years ago, like 28 years ago!

My wife and I had just got married about a month before and her sister and then boyfriend wanted to stay the night with us at our apartment. I was reluctant because I knew she was no angel like her mom and sister thought, I saw it in her eyes! I married the angel of the two unfortunately. She needed a way to have a night with her boyfriend away from her parents. Anyways, we all ate pizza for supper and watched a movie. We enjoyed the casual conversation and back and forth banter as young adults. We were only a few years apart. Honestly I think the boyfriend was closer to our age than hers. She was the youngest of the crowd being barely 18. Then as we decided to retire for the night I went to the bedroom as we had a one bedroom apartment so they would be in the living room on our pull out sofa. As I was laying in bed both girls were in the bathroom changing for bed as her boyfriend was doing so in the living room. Well the sister in law came out first in the shortest T-shirt she could find of mine and a thong! You could see everything in the front and back and what a sight. I knew he was getting lucky. She was built like a brick shit house at the time. She went to a gym for kickboxing three times a week so her legs were toned, butt firm, tits perky and about a full d cup! The whole package I instantly got hard when she walked out! My wife followed in a sexy white satin nightie with matching panties. My wife shut our bedroom door after her sister left. My wife then came over to the bed and straddled me realizing I was already hard and said well is that from me or my sis? I said both with a smirk, she said I bet, she didn't leave much to the imagination with that outfit did she. I said no ma'am with a chuckle. It didn't take long before my wife was grinding on me and had herself soaked and ready for action with a few passionate kisses. She whispered in my ear if shes getting fucked so am I. I took that as a cue i flipped her over got behind her and fucked her doggy till I felt her start to spasm around my cock. I wasn't done yet so I pulled her up and rolled her over into missionary position and continued till I was ready to cum she wanted it deep inside so she wrapped her legs around me and pulled me tight against her so my seed was planted deep within her. She wanted to be impregnated so bad.

After me and the wife had some fun, I needed a drink so I made my way to the kitchen and that's the first time I saw my sister in law naked. As I walked to the kitchen for a beer there she stood holding the fridge door open getting a drink herself naked! I looked her up and down and she did the same to me. She had a few big globs of cum on her massive tits, I asked if she needed a wash cloth from the bathroom she looked down. She then proceeded to take her finger and scoop up the cum and lick it off her fingers. She said next time it would all go down her throat, this time he was too quick. She said it seems like you have a little bit of something extra left on you too. I look down and see my Cock poking through my boxers but it's glistening with mine and her sisters cum. I say well maybe I need a washcloth. She reached down wiped it once and brought her hand to her lips and licked it and let out a moan then said hydrate and go fuck my sister again because I am fucking all night. Then she turned towards the living room, bent over, shook her ass at me and walked away.

I went back to my wife Many more stories to come, that's the start of my Sister in law obsession and almost 30 years later I am still obsessed! She knows what she's doing!