I'm looking for an expression which means to fall but describes how you fall and lay on the ground. In french we say s'étaler au sol, or s'étaler de tout son long, do you have something similar?
Hildy, I prefer your try to "spread oneself all over the ground"); how about "to fall flat on one's face"/"to sprawl on one's face"? P.S, ganieda, it's "to lie, lay, lain", not "to lay, laid, laid". (I bet there's an entry in our WR FR-EN dictionary about 'lie/lay'!)