boil? Keeping the lines and drawings constantly moving like in this:
[link]So even on a static pose, you would maybe draw the same image 3 times just tracing it freehand, and then you can cycle those 3 drawings forever and it makes the line boil like the drawing is still alive despite it not actually doing anything.
So maybe this could help those movements where...as you say, you have been lazy lol. While you animate some sections of the body and leave parts static, you could make the static parts boil by just adding 2 extra drawings of the same pose and cycle just to keep it all alive. Either that or you may very well need more frames, maybe more cushion and anticipation.