I'm usually already laughing my ass off by the time I hit the ground, so there's no breath for an explanation. Once I fell down almost on top of a girl that was walking by. She must have jumped 3 feet backward, and squealed "oh my god! are you ok?" I couldn't even say "yeah, i'm fine," I just nodded because I was laughing so hard and trying to wrestle my foot out of the toeclip while the bike was on top of me.