Another oldie but goodie is to physically bite their nose while in full mount. You can choose to bite it off fully at your discretion. Look at what a little bite on the ear did to "Iron" Mike Tyson. Image that was your nose and realize you're not 10% as tough as Mike.
Hmm? If I remember correctly, and I'd like to think I do, Iron Mike was the "bitor" not the "bitee." Holyfield was the one jumping around the ring crying to the ref.
This actually bring up an interesting point. A few years ago I attended a James Williams seminar. At one point he said, "We all know how to stop an MMA guy, right? Just poke him in the eye or kick him in the testicles. They've all been conditioned to stop fighting when that happens."
I don't think he was wrong. The sportification of MMA has resulted in predictable responses from those who practice it. One should never disrespect the strengths that they have, but one shouldn't overlook the weaknesses either.