A guy is drawn with an absurdly huge, equine-style dick, usually with a long tapered shaft and a big flared head that makes his partner look completely outmatched. Scenes tend to lean into extreme stretching, rough fucking, and the obscene volume of cum that comes with that kind of monster anatomy. Sometimes it’s attached to an actual horse or a centaur, but it also shows up as a “human with animal cock” fetish design.