Taboo

The changing room you brought your sister to was spacious and clean, with a locked door and strangely enough a king sized bed. Previously, you had made a reality alteration using the Omni app before meeting your sister that made it so that all stores are required to have a special changing room that is large, has a bed, is sound proof, and is always perfectly clean in case the customers who use it make it dirty.

"H-hey I was just joking about the bet I was just teasing you"

"Like I give a damn I'm getting my reward no matter what"

Intent on not letting your sister worm her way out of this bet you **** her to follow your demand. Watching your sister slowly and timidly remove her top and then reach down to pull off her pants you silently pressure her to continue when she hesitates.

Once your sister is left with no more then the surprisingly not seductive underwear you start to take pictures of her as a bargaining chip to use in the future.

Once thoroughly humiliating your sister and getting many photos to use to get her to do your chores in the future you let her put her clothes back on, an act that causes your sister to be surprised and even a little...

"What is that it...?"

"What you wanted me to do more?"

"N-no I, I just thought that-, you know what never mind! A virgin like you wouldn't have the balls to do anything else anyways!"

Taking her insults in stride as you now have those photos you turn around to leave causing you to not notice your sister rubbing her pussy and noticing a bit of moisture on her hand.