It was a hot, sweaty night that night. It's always really hot around here that time of year. Our parents were out of town, and me and my sister(at eighteen, a year younger than me) were watching TV. Even with the lights off and the AC on full blast, it was like an oven in there, and we were both completely drenched in sweat, so much so our clothes were completely soaked. Finally, my sister had enough of this.
"Jesus Christ. Bobby, don't look."
"Huh?"
Suddenly, she stood up, and took off all her clothes. I instantly looked away when her top came off, and her boobs came bouncing out.
After sitting down again, she said, "I mean it, Bobby, I better not catch you staring at my tits."
"Like I really wanna look at my sister's tits. Don't be revolting."
I tried to focus on the TV, but I could still see her out of the corner of my eye, so I shifted around in my seat, to get her out of my field of vision. That worked for a while, but then I found myself compelled to glance in her direction. I fought that urge for a while, until...
"Dammit!"
"What is it, Jess?"
"This heat's making me really horny. Like, y'ever been so horny, your legs start spazzing?"
"Jess, gross! I don't wanna know about that!"
"Well, look, could you just concentrate on the TV? I really need to play with myself right now."
"You can't do that in your room?"
"It's way too hot in there. Look, I just need to cum, then I'll be okay."
"Never mind! Just do whatcha gotta, and leave me out of it!"