Well, you did say you were play fighting. As a result, you should expect nothing more to happen as he grabs your wrist. He might have a sinister bit of sadism in him, in that he takes pleasure in knowing you can't escape him. So... why give that satisfaction? Once he grabs your wrist, there is nothing else to do: he's not attacking you, so, there is no line of movement or attack. So, just stand there and stare at him, like, "ok fool... what are you going to do now?" kind of thing. (Don't really say that... then he'll take it to the next level). The reality is that he's traded a pawn for a pawn; if he needs that pawn, he'll let go. You don't need the pawn (because you're not really being attacked), so, just stand there.

If you were really being attacked, though, your strategy is quite different. Also, he'll have directionality in an attack, as well as momentum and balance. But dealing with this can't be explained in text - it needs to be demonstrated and felt in-person, and explained by a quality instructor.

Whatever type of wrist grab it may be, the basic rule of thumb " no pun intended" is always brake free at the location of the Thumb.

If it's an overhand grip, turn your arm up with palm facing the sky, then pull your arm quickly towards yourself, to break the grip where the thumb is.

If it's a underhand grip, this is easier because the thumb is already facing you, so just pull your arm quickly up towards you, this will break the hold at the location of your opponents thumb.

If the person is much stronger, then grab your own hand, for added strength to break through the area where the thumb is griping.

This is difficult to describe through text but I will try my best. Feel his center. Which way is he pushing or pulling. Or is he holding your wrist in place? With this information you can decide the best course of action. If he is pushing you, use his momentum slide to the side and shove him behind you using his elbow as an armbar to flip him over. If he is holding you in place, dive for his legs and use a double leg take down to take out his legs from underneath him.

There are various self-defense techniques that are extremely simple and effective. In fact the ones I listed are very defensive based. If you would like to be more offensive simply use your opposite hand to deliver a palm heel to the lower jaw and then as his attention is diverted rip your hand free and strike his gut. Also you can clutch his neck and drive your knee into his chest.

Essentially there are infinite possibilities and solutions.

-black belt in Aikido practicing for around 8 years

I can tell you quite a few different way to escape such a simple grab. Bu you are likely to do it wrong and be convinced that they don't work. No one is there to correct you mistakes. This is why you need an instructor to learn these things.

Dive fir he legs and do a double leg take down doesn't sound like advice from an aikido black belt.

It depends on the kind of grab, as there are different ways to grab a wrist.

1)Twist your wrist (either end of the wrist) to the direction of his thumb and somewhere around/outside the other four fingers.

2)Do a sudden jerk by moving your hand away from him.If he's tall bend your knees and jerk your hand downwards at the same time or the opposite direction from him.

I said either end of the wrist cause it depends on the situation.

Use your free hand to grab the top of your fist and then pull back against his grip and in particular against his thumb -- the weak link in most wrist grabs.

personally i would headbutt him something about someone gripping wrist drives me insane

If its only one hand, grab their wrist and peal off. If its both wrists then twist your wrists then yank it out and turn into him

Aikido. Or Boxin'

There is this guy and he we always play fight( as friends nothing more) and he grabs my wrist sometimes and I can't break free. Is there a way to break free from someone who is grabbing your wrist? He is a lot stronger then me. And there is really not much I could do honestly.

One wrist or both? There are many ways to get out of such predicaments.

Though here in the videos, sometimes the shirt/gi is grabbed, the application is the same. If your friend grabs one wrist, these techniques can still be used. Others are for 2.