This happens to me too. If I'm thinking off something and it gets to be too much, I flinch or I guess you could say my body 'ticks' and I don't know if it helps me forget crap or not but I still do it. Sometimes I don't have to be thinking of anything I just have so much anxiety and it feels like something built up inside of me and I just want to get it out really quick. Doesn't happen all the time, every day or even every week. Just sometimes.