The act of having gay butt sex with a person without you or the other person being considered homosexual. This is because it uses the "no homo" rule or clause which is added to the end of other sentences between mostly men including but not limited to "I love you" "Your eyes are beautiful" or "Sex?"
Matt: I'm bored.
Bob: We should play some Gears.
Matt: No I'd rather have some nohomogaybuttsex.