If he's biting you because he thinks you are horses, then I'd say you have more things to work on than just the problem of him exposing himself in public.
You need to teach him some basic manners and respect for you. I've never had a problem getting a stallion to "put it away" if I give him a couple of smacks under the belly with a crop. Used to be a little easier when showing Morgans, because we were allowed to show with a whip, & if the stallion forgot himself & started to drop, it was easy to give him a couple of discreet taps on the belly, just to remind him of his manners. Since we aren't allowed to show with whips at AMHR or AMHA shows, and since Minis can be a little more determined about "if you've got it, flaunt it"...we're very strict about this at home, so that if the stallion does decide to drop in the ring, a poke in the ribs with my finger will suffice to get him to put it away. If that doesn't work I'll (discreetly?) reach back & give him a slap with my hand, either up under the flank or at the top of the offending part itself. Have never had a problem with giving that a smack if all else fails--obviously I'm not going to lace it a good one with a whip & raise a welt on it, but a tap with a crop does no harm--it has never put a stallion off breeding.
I can remember at one Morgan show years ago, a friend was showing her 2 year old stallion that was barely halter broke & really hadn't been trained anything at all. Instead of the show whip most of us carry in the ring, she was using a short crop, with the folded leather end. While she was waiting at the gate her colt dropped. She was screeching "YOU PUT THAT AWAY RIGHT NOW" & then she took a swing with her crop, aiming for his shoulder. He jumped back & the force of her swing carried her right on around into a spin! Pretty funny to see, but I always wondered if about then she felt as ridiculous as she looked & sounder???
