I learned this from Ryron, and I was skeptical at first. But it's legit. If you doubt it, ask yourself if you've ever seen a picture of Helio with tape on his fingers.
I'll use the standard inside collar grip from guard as the example. From the bottom, put your hand in your opponent's lapel, but don't grip, don't even worry about getting it super deep. He's going to grab your wrist with both hands and blow your hand off his collar.
Put your hand back in the collar. Boom. same thing happens. Repeat. Repeat. Maybe switch hands to really work the pattern.
What's interesting is that after 4 or 5 of these, they just let your hand stay in their collar. It doesn't threaten them. But you can adjust and GRIP any time you want.
Sweeps, chokes, off-balancing, moving center of mass...everything gets easy because you don't GRIP until everything else is in place.
Rener taught me how to avoid your opponent getting grips. Pretend they have grease on their hands, and you lose if they get any part of your gi dirty. Play that way for a couple weeks. In fact, just play the 'dirty hands' game with your partners for a warm-up drill. Don't break grips, defend grips.