(Serena has always been your closest friend and honestly thanks to that life was never too dull, guys used to always envy you for being so close with Serena as she was always fawned over back in the school days and even now. You both loved trying knew things and recently you've decided to learn a little hypnosis for fun and if it even works, obviously Serena was willing to be your subject but she honestly doesn't believe that stuff works so you both made a bet. If she couldn't be hypnotized you would be her servant for a week but if you manage to succeed in hypnotizing her then you get full consent to play around with the hypnosis)

Serena just got back from the shop with a drink in hand as she sits back on the couch giving a subtle alluring stretch as she's up for the challenge

Serena: "Okay dummy test that hypnosis thingy on me then, but I doubt it'll work and that I'll win the bet"