Jenna strained back at me, reminding me I had more important duties. I straightened and rested my hands on my little sister's tiny bottom.
"Remember the rules," Amy said.
I looked over at her quizzically. Amy was sitting on the bed, off to the side. Still fully clothed. She arched her eyebrow at me.
"Five pumps," Amy said, "Give her the feel of it, but that's all. That way it's... innocent. Not, ummm."
"Incest?" Jenna asked, her voice cracked.
"Right," Amy said, "It's just siblings learning together, you know? Nothing wrong with that."
I drew back slow, same as I'd done with Brianna. As I slid back in, Jenna started breathing hard out of her nose, like a bull getting ready to charge.
"Harder," Jenna said. She had her head bowed straight down.
"You sure?" I asked. Jenna reached back
