When an individual reaches the top of a set of stairs only to incorrectly think that another step requires surmounting, the resulting leg movement that then arcs upwards and outwards could be said to resemble the manner similar to that of a horse when counting with a foreleg.
Just walked up to level 2 and caught some serious air horsecounting as I arrived
Pornography depicting and directly involving equine.
An exclamation used in situations similar to "fuck!" intended to arouse a greater amount of shock among audiences. Great for surprising nearby folks and making them feel akward.
Also can be used to describe something as being BS or meaningless
Person 1: Dude, there was gum on that bench you just sat on.
Polite euphemism for horsefucker, often used at dinner parties and other genteel events. If Eric Cartman had said this he wouldn't have been shocked by the V-chip.
It might be possible to combine horsemounting with sado-masochism and necrophilia, but that would just be flogging a dead horse.
"I really don't get disgusted by a bit of immaturity in a game. I got a chuckle playing Horror of Rylvania when the game called me a pervert for trying to fuck the horse. Mostly just because it was unexpected. And hey, *mounting* the horse actually netted me a useful item!
MH (the horsef...errr....horsemounter)"
(from rec.arts.int-fiction)