It was a smell that I was extraordinarily familiar with - for the past several months, I’d been helping my brother with an unusual medical condition...My brother, you see, can’t cum when there’s someone else in the room.At first, I’d tried helping by just sitting in the room while he masturbated. We’d always been extraordinarily comfortable around each other, and so it made sense that if he could get off near anyone, it would be me, his little sister.It hadn’t worked though, and so we’d started. At one point I thought they were going to kiss, they got so close. But Helen pulled away. She looked round, saw me watching and smiled. I smiled back to encourage her. She looked so sexy, flirting with another guy and getting ready to fuck. My cock was rigid. Suddenly the guy stood up and headed for the toilet. I rushed over to see what was happening. Helen was flushed and excited. She told me she had told the guy that she was married and her husband was with her. If he didn’t mind me watching. Then I told Sam, “You don’t have anything to worry about, I should be able to give you a good lead time when we do this for real.”Sam and I were very interested in seeing how the lines acted in the VIP area. The patrons were indeed much less agitated in general, but as the time clicked down to the final minute it did indeed heat up again. There were much fewer people involved, and Sam said he was feeling good about it overall.We turned our attention to the track as the race began, and enjoyed. She sat with her legs crossed so they could see a little bit, not sure if it was panties or hair they could see, I'm sure.The place was small enough that I could hear the boys talking.One said, "Holy shit is she naked underneath?"The other said, "Oh shit I think I can see her cunt."It's not my favorite word but that's what he said. I have to say these guys were truly amazed at what they saw.Marla's pizza was ready and she got up opening her legs and turning in her seat showing them a full view.