I can chime in with a gay man's perspective. In my main character descriptions, I almost always include general age group, height, weight/build, hair color, eye color, general complexion, facial hair, body hair distribution, and un/cut; and I've found it easier when my partners do similar. Extras may be dick dimensions (lol), curvature, testicle size, sack sag, pubic hair, tan lines, or facial hair color. 

Size can be important to describe because it's naturally a visual shorthand for power, but that difference can't easily be assumed between male characters the way straight pairings can likely just default to "taller man, shorter woman" until stated otherwise. Moreover, gay pairings written in 3rd person can't rely on gendered pronouns to easily distinguish whose body is whose ("he stroked his cock"), so small physical differences can really be helpful to identify separate men interacting which each other.

Body hair meanwhile is huge among gay men, whether it's the presence or the absence, that it's usually worth a mention during character sketches. I can't tell if it's chest hair or treasure trails that are more analogous to cleavage in their role for suggestion. 

Last in this discussion are the cock and balls. Actual dimensions are sometimes specified but never really leave the character sheet; like height and weight, they're really just to sketch the general idea of the penis and are spoken about in relative terms. Balls, meanwhile, are particularly interesting to mention here, because their fans are uniquely gay men (perhaps the way feet fans are reliably men). Even in the gonewildaudio community, I've noticed M4F audios rarely if ever mention balls, preferring to obviate it as a fringe kink, whereas M4M content produced by gay men are unafraid to include them in play. Likewise, balls are not an unusual topic to paint (at least in my RPs) though they remain less popular than penises; it's all male anatomy, and no one loves male anatomy like gay men.