When I feel a sneeze coming on, I brace myself, whether I'm in the midst of a flare up or not. I usually lean forward, and hang on to the counter, table or back of a chair. Better than that, though, is to squat down, curving my spine as much as I can before it happens. Sometimes, they come on so fast, though, that I don't have the time to brace myself for it, and the pain is so bad it literally brings my legs out from under me! It's like someone stabs me in the lower back and then runs the knife down my legs! Talk about painful!
It's funny, even some of the things that seem like 'little irritations' when I am going through them seem to be validated as real through this board... It just reinforces the belief that I'm not alone!