Re: Not being challenged as Uke?
Who are you working with?
If I were working with another black belt, I would get up if I could. If I couldn't, I would tap whether it hurt or not. If you're flat on your stomach and immobilized, you're pretty much at the mercy of whatever nage wants to do. Why encourage him to hurt you?
If I were working with a beginner and didn't feel I was pinned adequately, I would walk them through some suggestions for a more effective pin.