Here's a bit of an idea for you
Look through your house for some duct tape, electrical tape, or the like, then take it back to your room (without any family members seeing, of course).
When you get there, each of you put in a vibe, set them on high, and use the tape to keep them in place.
Then, see, who can go the longest without climaxing. Whoever last longer has full control of the other for the evening