the subsequent nasty sensation left lingering in one's mouth after performing fellatio (hopefully experience by a female).
Girl 1: "After he blew it in my mouth, I had cockon-mouth for at least an hour!"

Girl 2: "Yeah, but didn't he have it in your ass right before that?"

Girl 1: "Ohhhh, right. Doh!"
by position_x_force February 25, 2005
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