Medic knowing he's a disgusting bastard from the get-go, but that only turning him on further. Thinking about how if he gets caught he'll never live it down. Especially if he happens to be on Engie's ranch, though I see Medic as more of a fence-hopper for any nearby farm (that has horses). Bet the first time he cums during the rimming it's while getting a faceful (and lungful) of ass gas. Hands-free too, every time. Using his free hand to jerk off the horse instead of himself, moaning into the puffy, smelly doughnut. Going from starting off with nervous licks constantly looking over his shoulder to getting more into it and lost in the sheer pleasure and humiliation of it all. Starting to nuzzle his face into the hole, take long whiffs (during at least one just so happening to get farted on again and inhaling the entirety of it), peppering kisses all over and wishing he was wearing lipstick just so he could see the kiss marks, suckling on the ring. Legs turning into jelly barely holding him up as he stands there continuing to worship that horse ass, hips bucking and humping the air, only aware of his own orgasms after they happen not even realizing when they're building up past the first one. Being unapologetically loud and moaning into the ass, only getting snorts and whinnies in response. Medic's having the time of his life while the horse couldn't really care less, maybe finds him slightly annoying especially if it's late at night and it just wants to sleep. But he's gotta be doing something right with his tongue and lips and hand, to not be getting bucked away.

Then the next morning one of the mercs noticed his disheveled face and asks why he smells like a barn.