Retribution
You were gonna kick his ass. What kind of friend asks out the girl you’ve been crushing on for months? You told him more than once you were going make a move and he just did it anyway. That asshole. This was yet another douchebag move from your best friend in the last six months and you were over it. It was time for a beat down. Of course, he’s nowhere to be found and not even his sister knows where he is. She’s pissed off at him too and fully approves of him getting his ass kicked. But there’s nothing either of you can do until he gets back. The two of you reminisce for a while… a tickle war ensues and suddenly you’re on top of her. You can feel her body melting into yours as your dick presses into her. He would be so pissed if he found out you fucked his sister. She smile’s as she pulls her panties to the side, “What better way to get back at him?”