"I bet you can't get your room-mate naked for the evening." - Easy money.
"You'll never get her to lick up cold custard from a plate for a video." - No sweat.
"I bet you and your room-mate won't les it up and post it to FaceAGram." - I can pay my tuition fees at this rate!
"I bet you and your room-maye won't let me tie you up naked back to back on the bed and take photos!" - Challenge accepted!
Although the gags weren't part of the deal....