She was wearing a tight t-shirt and shorts. I was able to see her deep cleavage. I was getting horny. By time it was 11:45am. And I asked my sister (I... really want to ask u something if u doesn’t mind). She said okay bro ask it? I said I like to have sex with u. She was shocked at the moment. She asked me are u mad? I said no, I really want to have sex with u, so I convinced her, what is the need of sex between brother and sister.I was tell her all those sex stuff, but I didn’t brain wash her or. She dressed a bit like a skater punk, but that in no way subtracted from her innate beauty. Over the course of the night, I killed the bottle of Crown Reserve, and the spliffs were having a nice effect on me as well. Eventually, my buddies decided to leave, but I was enjoying myself too much, and I couldn't drive in the state I was in, so I decided to stay, with the plan being to crash in Rachel's guest room. As the party continued to dwindle, only a few of us remained. We headed inside to play. I said yes but she wasn't really game for my top choices which were both threesomes, MMF and FFM. Jason seemed shocked that Sarah (who was very sexual when alone with me) was not fond of the idea of either. Jokingly I told him that maybe we'd get lucky and she'd come home plastered so we could have our way with her. Don't get me wrong, I would never take advantage of her but she gets especially horny when she's had a few and is more willing to try new things. Jason thinks for a minute and say's. "Mark!" she reacted without thinking. "Yes?" I said. "Do you want to go back on the deal?"She was clearly struggling, but after a minute she said no. I tookthat as my cue and I reached behind her and unhooked her bra. Herperfect breasts fell out, and I saw that her nipples were standingstraight out. I wasn't sure if that was arousal or just thetemperature, but I decided to take it as a good sign. I took herbreasts in my hands and squeezed them slightly. "Not bad, sis," Isaid quietly. I.