Well, not sure what you would call it, but under extreme stress, i either cant sit still, am pacing, will drive somewhere and when i get there will drive back, like mind doesn't know what to do.. will shake arms, like doing a warm up for a 100m sprint! But generally will close myself off in my room, and talk to myself alot, full body shakes, but younger, i would scream if parents tried taking me into a busy store, always had issues with shops in general/busy places, have got much better though but still get the anxiety build up and muteness, but still avoid if i can or will go and do shopping at the quietest times... There is certainly one trigger i have and that happened again recently, the worst part for me is i never know when it will fully stop, sometimes it days even weeks and months, depends on the level of stress and when it subsides... I never outwardly intentionally or unintentionally hurt anyone, im too caring about others to let myself ever do that or even think about it.. I just think i wouldn't want them to feel what i was feeling, but this amplifies the inwards emotions i feel, but there is no other option... leg bouncing/foot shaking is definitely a constant as is nail biting, only ever had them cut once in my life... But generally all the above i try to keep as private as possible. My "Tomb" (bedroom) is my sanctuary aswell as nature and water if i have the energy to venture.