Being "gar" doesn't mean being manly. The term comes from a misspelling of "gay". The idea being, a male character did something so manly, so heroic, that you were able to suspend your heterosexual-ness. I think this originated on 4chan, but don't quote me on this. For instance, Gurren Lagann fans could be said to be "gar for Kamina".
I guess it could be said that a character being "gar" means he is acting in such a way to make you "gar" for them, but that's not how the term originated.