She went straight for the hot tub on the deck without turning the lights on and we could see her because we were sitting in the living room. Only a wi...dow separates the deck from the living room. She took off the towel and hopped in the hot tub while everyone was looking with disbelief. Although it was dark on the deck we could still see her breasts and her nicely shaved pussy. Todd was the first to break the silence saying he wouldn’t mind a nice soak in the hot tub right now. To everyone’s. Stacy still wore a pair of bright red panties, though nothing else, as Bob, Brad, Billy, or Butt-head sat fondling her tits, his rock-hard cock begging for attention, which for the moment, Stacy was obviously neglecting, enjoying the attention he was giving her tits with his mouth, along with the hand that now reached over, cupping my sister's groin as she sat there next to him.It was seeing that which had aroused me beyond measure. Stacy's boyfriend, fingering her pussy through those red. The first one was the most powerful, and shot up and landed between her tits, as I started to say "Oh my god". The second one shot straight onto her stomach. "What are you doing here" I said. The third also went onto her stomach. "This is so embarrasing" I continued. The next one landed right on her panties where her pussy is. She starts to laugh and say "wow that's a lot" as I pumpt the last drops onto her panties. Now I can see her in full, with my cum dripping down her body. Her tits are. I opened the door and let him in then I asked if he wanted a cup of tea, trying to put off the painfully embarrassing moment when I had to tell him what I had done. Then he looked at me and I blushed deeply."And just what have you done?"I looked at dad, this was the moment of truth. I lifted my tee shirt. "I can't get it undone and I need to get it off." I can see your problem, indeed, why didn't you loosen the ties at the back, it would come off quite easy then?" I didn't want anyone to know.