How It Works
Firstly, the controls would be simple...block and hold the right stick left/right to hold position. Position holding will work hand in hand with the current system, so it will just be another option. You'll be able to hold position or deny at your own choice. Also if you're holding position, you'd be able to let go at any time to attempt a denial. Of course you'd have to be denying in time before the opponents transition goes through. The way I see this being implemented into the current EA UFC grappling system is by allowing it in certain positions only. Like more simple positions where we see guys trying to hold position irl. The upside to holding position is it will allow you to block any transition attempts. The downside is that blocking transitions with it won't grant GA like denials do and that it will also drain your short term stamina. Once your short term stamina drops below a certain threshold, transitions will automatically get through. This will make position holding more of a thing that has to be used strategically.
Positions It Could Be Used In
The positions I think holding can be used in are the more basic ones and the ones we see fighters try to hold and maintain irl.
Top Positions
Holding position from top would be able to be done postured down or after you break an opponents posture control.
DOM Full Guard: As you can see in the gif below, guy on top keeping his head/body down on the opponent to maintain pressure, stay heavy and hold position...
DOM Half Guard: In gif
A, we see a close up look at head & arm control, which is used a lot in half guard and side control to keep pressure on and hold opponents down to maintain position. Then in gif
B, see how the top fighter passes to half guard and right away grabs that same head & arm control, to hold down the opponent and maintain his new position.
A
B
DOM Side Control
Just like in the half guard, head & arm control is used a lot in side control to keep pressure on opponents and maintain position. Below we see it being used by the guy on top to maintain control of his opponent...
These are the three top positions I feel could use position holding. All other more difficult to hold top positions like mount, back mount, crucifix, ect would use strictly directional denials.
Bottom Positions
Now position holding would be more situational from bottom, as you'd only be able to do it when the top fighter's posture is down.
SUB Full Guard
Bottom fighter would use body locks or head&arm control from bottom to try and keep the top guy controlled...
SUB Half Guard
Similar to the full guard, bottom fighter would use body locks or head&arm control to try and keep the top guy controlled...
SUB Side Control
Now holding from side control bottom will work a bit differently. You'd only be able to block certain transitions in this position, as you can't really "hold" from here. It would let you put a knee up as the bottom fighter, blocking all transitions in the direction of your body. So that means it'll block mount transition, kimura, ect...
SUB Full Mount
This should really only block posture up attempts by the DOM. We already have holding from mount bottom, but it doesn't really block the posture up attempts...its like one attempt and they get out.
These are the bottom positions that I feel could use position holding. All other bottom positions would use strictly directional denials.
So those are my idea's on how position holding could work. Just some thoughts, as lots of players including myself, miss that aspect of the grappling from UD3 where it had that immersive feel of struggle and trying to control an opponent.