We had already bought condoms but we said thank you to my dad as we would use that money on other things. We finished breakfast and then headed to the...cottage where Mark and I packed a bag with extra clothes incase we slept over. We had two boxes of condoms in the car and one each in our wallets as we made our way to say goodbye to our parents. Once hopping into the car Marks phone rang. It was Danni asking what time we would be by them or if we wanted to meet them by the mall to get everything. ”She yelled back, “Stephanie is always late so don’t worry.”A few minutes later she came out of the bathroom dressed. I gasped when I saw her. My mother is always gorgeous, but tonight she was positively radiant. She had on a pale blue Grecian style gown that touched the floor. The top covered her right shoulder but left the other bare. There was a split that went from the floor all the way to her hip on the left side. Then I saw something that made my mouth drop open. I could see the top edge. Night after night I woke to my sheet getting wet with my jism. I tried to wipe it off with Kleenex, but it always left a stiff patch on the sheet. I used to take the sheet off and wash it when my mother was out, but sometimes had to leave it only to add to the stain the next night. I tried to masturbate just before I went to sleep to no avail; wakening to the wet spurts from my penis, anyway. I had some success wearing two pairs of briefs to bed. I shot my cum into the underwear, but didn’t. I could hold it no longer. I tensed every muscle in my body as I felt my hot cum explode deep into my step sister's wet pussy. I felt her bite down on the top of my shoulder as my fluid filled her womb."Ohhhhhh godddd yesssssss!" Ally panted in my ear again. "I'm going to cum on youuuuu!"I felt her legs and pussy muscles tighten around me as her body was rocked by her own orgasm. I felt her warm juices running over my cock.Ally pressed her mouth against mine hard and we kissed deeply. Our.