I had a FWB years ago that enjoyed a special sort of play we called “Bitting Up”.
She wanted me to bit her up with the horse bit that “pony girls” like. I put the tall leather collar around her neck and buckled it up. I had her put the rubber covered bit into her mouth herself, hold it, while I buckled it tightly again behind her neck. It’s about 3/4 “ in diameter and sits well back in the mouth between the molars. Forces the mouth open, and draws the cheeks back when properly placed.
The bit has two large, metal rings attached to it. I brought the reins over and fastened them to the rings. The reins have these metal clips that make a loud clicking noise when opened and secured to the rings on the bit in her mouth. She gets very excited at the entire process. Starts to breath harder, cunt starts to drip.
I will then always lead her around the “ring” to get familiar with where she is to demonstrate her knowledge of being reined from behind like a horse. She leans over perpendicular to the ground, and puts her hands behind her back so that the forearms overlap and I will loosely tape them. I want her to be able to get her arms free free if she stumbles.