When 2 bros sit side-by-side facing forward (sometimes in a moving vehicle), and use the arm closest to one another to reach over and give the other a hand-job. As this happens simultaneously, their arms cross each other, forming an "X," hence the term X-Men.

{First off, I sometimes wonder if this Urban Dictionary was created as some kind of breeding ground for idiocy...

In the Marvel Universe, A particular group of Mutants (Homo Superior as opposed to Homo Sapien) with special abilities who have grouped together to defend humanity as well as they can. Although a significant portion of humans hates mutants, they still strive forward to show mutants are not all evil as many think.

a guy especially an ex boyfriend that does not have his shit together and has no direction, immature guy in his 30's, a jobless 30 something male

A group of mutant superheroes who are all gathered in a "school" (doubling as their headquarters). They fight bad mutants, bad humans, and retards that think they suck on peoples' anal cavities.

A bunch of overly muscular mutants who can't have sex because they might kill each other by means of explosion/touching/stabbing/electrifying/freezing/burning etc.

Term to describe transexuals or ladyboys

(ok why would Xmen be slang and who cares if it is)
A show that is on ABC Family that comes on the air it was on the air in the '90s and in to 2000. it also has a bunch of movies that little kids see