I don't have any ideas, but I can see how tying someone up in their sleep could be fun and not a total violation of trust and all that. I would love to fall asleep cuddled up next to somebody and then wake up inexplicably tied to my bed. Rawr!
what's that old saying? "you can't wrape the willing..."
i have no saran experience, but i think an early hidden setup would be helpful. try using several rolls, and pre-feed them all between the mattress and frame (and then hide the rolls under the bed). that way, you'll be able to toss them over top of the person while he/she is still asleep.
and use the punch-in tabs on the sides of the box, dammit. they're there for a reason!!!
That method could be difficult to make tight.. But is possible. I mostly wrap my lee to a a chair, it gets him really stuck! that would be even harder to do as a prank, I just love the idea of him being completely covered and waking up all confused 😛