Punishment.

"Don't you remember?" Cindy asked, standing completely naked in front of her brother.

"Remember what?" Callum inquired with a puzzled look in his face.

"Mom's punishment. I'm not allowed to wear clothes in the house anymore, including my knickers. You were there when she gave out the punishment."

"Oh yeah, I remember now." Callum said.

"She also said, if I ever get aroused, I must masturbate there and then, regardless of who sees." Cindy added.

After Callum 'remembered', Cindy once again straddled her brother sitting on the couch. He immediately began caressing Cindy's breasts again, massaging them, squeezing them, tweaking and lightly pulling on her nipples. Seeing as her pussy was already drenched, Cindy just plunged her middle and index fingers into her slit and slowly moved them in and out. Cindy was in paradise, her body completely taken over from the pleasure of her brother groping her tits and from finger fucking herself. Cindy was living out her fantasy, finally able to have her brother all to herself. Cindy was tasting her cake, the cake was not a lie. ;-)

Pulling her nipple a little harder than expected, pushed Cindy past her breaking point, she came harder then she ever came before. Her cum burst out of her puss, drenching her fingers and her brother's jeans. Eyes jammed shut, Cindy rested her head on Callums shoulder, completely drained, but satisfied.