1. An expression used to define something detrimental to someone's career or livelihood.
2. Any action that has a harmful effect on oneself or others around them.
Taken from Daniel Radcliff's decision to star in London's revival of Equus, a play about a teenager with a sexual attraction to horses, causing parents to refuse to see any more of the Harry Potter movies in protest.
the act of sexual intercourse in such an extreme and brutal manner that it is reminiscent of the shameless, horrible, bucking, snorting, hair pulling, biting style in which equines mate.
Ned: Hey dude, did ya get laid?
Ed: Due, I was horse fucking that bitch til she was ripped apart, screaming in agony, and still begging for more. I don't make love, my dorky friend, I horse fuck 'em.