How common is this?

[marques]

Also, if someone traps your hand like this and then throws a punch, what is the counter to it?

First of all, we should avoid that oportunity for the opponent - distance management, footwork, closer guard, keeping him busy...

After the trapping, I would rise the shoulder and lean the head / body. I think it happens quite often in MMA. But it is not a counter.

As a counter, I would kick the knee or body (if... because longer weapon). Puting him a bit cautions or off balance is enough, defensively.

 

[FriedRice]

This seems like such a simple technique and although I know it's probably really hard to pull off in an actual fight, is this sort of thing common?

Also, if someone traps your hand like this and then throws a punch, what is the counter to it?

I like using this against Wing Chun guys. Parry the lead extending hand to come in with an overhand right.

One defense is train to draw circles with your hands, like how BJJ warms up doing leg circles....it defends against dudes trying to grab onto your gi pants.

But this big dude threw the OR, right away...he trained for this tech.

Another good defense against an OR is to deep shoulder roll while popping the lead elbow up....but it's caught, so you just have the DSR....so just tuck the chin behind the shoulder, squat low and back onto the rear leg.....rear hand cover the face, palm out.... and brace for impact.

Then he's In a nice position for a take-down.