It was late, or early on sunday morning, depending how you look at it; when my step-son and his gf came in, he was clearly drunk, very drunk and staggered upstairs to his room, probably without even seeing me in the kitchen. His gf, Stacey, sat on the shoe coffin, to take off her heels, she is around 5'3" tall, long blonde hair small tight breasts and a very pert bum. Tonight she was wearing a tight white top, over a plain white bra and a short pleated skirt. She was having real problems getting her 3" shoes off and as I went towards the door, I could see her sat on the coffin, legs apart, no knickers and a lovely wet sight winking at me. The noise upstairs finally died, so I knew he had dropped onto his bed and gone to sleep, he isn't a drinker, so much different from me at his age. I quietly asked if she needed any help, 'what like the help I've had from his pals?' she replied with a slur, I asked her what she meant and she just said no knickers. I bent down and undid the strap on her left shoe, at which she kicked her foot out of it, as I went back to do the other I had to put my hand somewhere, it happened to go onto her leg and she let out a low moan. Both shoes off she tried to stand up, she wasn't as drunk as he but she was still drunk, I held her waist to steady her as she stood facing me, she seemed like she was going to fall and threw her arms around my neck and we were now very close, the alcohol didn't smell nice, but the perfume was very alluring. I pulled her back into the kitchen, it was then that I really appreciated my grand-dad pyjamas, my cock was rock hard, I moved my hands down and lifted up her skirt, she lent in and kissed me as my finger began to work along her slit, being early 20's she was very quiet as I pushed my finger into her working her clit with my thumb, she tensed up and came, without making a sound, I dropped back onto a kitchen chair, she fell on top, straddled and my cock found its own way in. We didn't take long, her rocking back and forth and me trying to push it as far in as I could, but soon I was shooting up her. She let out a little giggle, 'two of his mates and his step-father in one night.' she gave me one more kiss then, almost soberly stood up and went up to bed.