Not sure if this was mentioned before but one of the more extreme examples is from a Czech tv move called Dopisy v krajkách (2003). Not sure whats being said throughout but the main plot involves some noblewoman being trained/degraded to act and live as a horse until she begins to go along with it. Around the 26 minute mark, a stallion is brought to her while she is naked and with a small audience. The stallion immediately gets a hard on while she leans against a small wooden fence and spreads her legs apart and the stallion approaches her from behind and rears up with his boner. The act itself unfortunately isn’t shown but you can definitely hear the woman gasp out loud and the horse railing the shit out of her
. Great for the imagination