I'm trying to remember, but I think I only fell once. Virginia, Minnesota. We did two nights at this place, called Rendezvous II. The roadie had taped the show and the club had a big upstairs apartment area, where the band slept. We were up there watching watching the show on tape and it was a Gene song, I'm thinking "Calling Dr. Love", because the guy who played Paul (Eric) and I were doing vocals on one mic, while Gene was singing. I start to lose balance and start going down. You can see on the tape that Eric reaches out a hand to try to help me, realizes I'm going down regardless, and that if I grab his hand he's probably going with me, so he pulls his hand back and keeps playing and singing as I fall out of view.
I'm pretty sure we must've rewound and watched it a good ten times or so.
EDIT: For those who don't get the reference, I used to play Ace in a Kiss Tribute band. In the pic
here, I'm on the far left.