You noticed that Chad was looking with disgust at Jen's cock. You never had anything against him and just wanted your sister to notice the changes, you waved your wand at him. With that his expression changed and he said "I'm seeing that you're really excited." and then start sucking on her dick.
"Hey, what do you think you’re doing Chad?" Jen asked due to the unexpected reaction to her.
"I'm just sucking your dick like I always do." Chad said
"This is a lie. I've only had this dick for a few hours." Jen said
"That joke was good. You don't seem to remember that we met when I caught you jacking off at school." Chad said and went back to sucking her dick.
Jen knew it was her thing, but still nobody said anything else until she came. Chad later commented on how much he liked having her cum on his face.
After the orgasm, Jen remembered that you were seeing everything, cast an angry look at you and sent a message to your cell phone saying: "I want my vagina, right now."