An euphemism for fellatio, oral sex, an act performed by a person on the penis of a male, the opposite of cunnilingus. The term was created by “The Man” and has become popular due to its frequent use on the legendary podcast Slacker and The Man. It is important to this podcast not to offend their sensitive listeners, many being doctors and lawyers.

Terminology: A headbutt is a strike with the head, typically striking a sensitive area of an opponent. A unicorn is a horse like animal with a long horn believed to have healing powers. If you haven’t figured it out yet, unicorn is another euphemism for that most honored part of the male anatomy, the penis. Put the two together and it is easy to create an image in the mind of a woman charging with her face first into a gentleman’s lap - the beginning of oral sex on a man.
FNG: Did you see that chick in the Poison Ivy costume?"
Snuggles the Fister: "Yeah, she is totally going to headbutt the unicorn tonight."
Mashers: "What's headbutt the unicorn?"
The Man: "The opposite of headbutt the buffalo."
Dobbs (singing): "Show me how to blow dudes, blow dudes..."
by Mashers69 March 28, 2014
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