Assume her eyes are closed and rub my cock?

Taking a pretty big chance, I assumed her eyes were closed behind her sunglasses as she lay there and I started to rub my hard cock over my shorts. I pulled the right leg of my shorts up my thigh and pulled my hard cock out underneath it and took it into my hand. She didn't react, so I began to stroke it lightly.

God this was exciting! I was stroking my cock while sitting beside Rochelle and staring at her in her bathing suit!

"What the hell?!"

I jumped about a mile high as Tim was standing at the stairs of the deck watching me stroke my cock to his mom. Rochelle sat up and may or may not have seen me putting my cock back into my shorts. She didn't show any sign of having seen me for the rest of the trip, but Tim was really pissed at me. He didn't say anything or demand Rochelle drive me home or anything, but he also didn't invite me to his house the rest of the summer.