He asks Lisa what she is doing.

“Lisa, what are you doing?” Matt asked getting a good look at his sister’s body.

Finished taking off her clothes she looked at him like he asked a silly question and said. “Getting ready for you to pump all your sperm into me. I’m your cum dump so I don’t need clothes.” She didn’t even know why she had put them on anymore.

“Wait so you’re never going to wear clothing again?” Matt asked as she laid down and spread her legs.

With a sigh she said. “They will only get in the way.” Looking at him expectantly she asked. “Now you going to pump me full of your cum or what?”