a certain fellow i frequently drill/roll with is extremely persistant on using cross collar chokes on me. it's getting to the point whenever he's in my guard (or halfguard, mount, etc) he's attempting to grab for my lapels and choke me out. it's really a nuisance because i'm constantly trying to fend it off - do you guys have any basic tips for stopping this? i've only actually tapped out to them twice, but because i'm actively fighting them off. do i simply have to deal with it? while i am basically just a beginner, this seems like some overexcessive use of the same technique - is this a common occurance? am i perhaps just leaving myself open to them, and if so, what can be done to prevent that?