This is good, we should be practicing some of this as, try as we might not to get grabbed, there will betimes when it will/might happen, at a party, club etc.
But I don't like to teach much against grabs, as subconsciously one might program the 'wait for the grab before I counter' _
I find it better to concentrate on sensing the grab coming and using the ghosting, evasive, techniques of getting off the X...
Defending The X is the first reactive option, and probably the least desirable as it is the most tenuous. It involves holding your ground and fighting from your existing position, probably because you have no distance advantage (he is just outside of arm's reach), no spatial advantage (you do not have the option of moving off his line of attack), and no initiative advantage (you are reactive, not having anticipated and prepared). While this is certainly an unenviable place to be, we cannot ignore the possibility of being there. If so, our first consideration, after the fight begins, will be to gain an advantage either in the spatial or interval areas.