Teeth weird

Hi all, I'm severely confused but this question is so stupid I don't want to bother my doctor with it. I took some mdma a few days ago, great experience, and it has of course left my system already. While I was on the mdma, i kept sort of vibrating my jaw to make my upper and lower front teeth rattle against each other, like when you're very cold, which was strangly fun in the moment. The confusion here arises in the fact that I still catch myself doing this once or twice a day now even though I haven't taken any xtc and so it cannot be an effect of the drug. Do any of you have a clue as to why?