You can't. The moreClothing mod works with the vanilla game's template system. sby has extended the template (to include legwear, overtops, etc) but there are currently no template categories for male clothes.
@Konashion didn't complete that aspect of the game before his disappearance, and nobody else has volunteered to finish the job (because male-costume modding isn't especially popular).
If you wish to load male clothing mods conveniently then I would recommend setting up a Character Folder, as described in the
Newbie Guide. You can setup a folder which contains
only a male costume (and then load it "on top of" your other customization work), or you can setup a huge Character Folder which defines a complete scene (girl's clothing, girl's body, background, custom dialogue file, male body, male clothing, etc).
P.S. The preceding answer assumes that you're talking about the
standing character. If you're describing a male character in the
kneeling role then he's eligible for moreClothing outfits -- and any customization can be saved via the in-game menu as usual.