When one gives a blow job, and the recipient cums on the "giver's" face, just below the nose.

This is also often related to gay sex, as mustaches are usually inherited by males, rather than females
That guy gave his boyfriend friend a cum mustache the other day
by BloodyTurds February 16, 2009
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when a girl is finishing sucking on the johnson...the man pulls out and sprays a fine line of semen all over the mouth of the women in the style of the got milk commercials.
u got a nice got cum mustache? there.
by beverly sex June 3, 2006
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