Gaydar, Straight Gay, and Outing Someone

Niccolo meets a student named Azzerello with whom he hits it off quite well. Niccolo decides Az is the best candidate for best friends forever for college and maybe later and likes that Az is good for punching people in the face which Niccolo likes when he's on a Screw the Rules, I Have Connections! rampage.

Niccolo likes having the buttons to push on everyone he knows regardless of whether he thinks he would need it.

He finds out Az is gay, but I can't decide how.

Az is on the Straight Gay side and generally doesn't make it obvious he is gay and is currently single. Niccolo figures it out by means of something not including catching Az having sex with another man. Niccolo isn't of the Mistaken for Gay sort either. I don't want Niccolo's Gaydar skills to be totally inexplicable. However, Niccolo tends to skew paranoid and suspicious because he is accustomed to his family's organized crime dealings.

Currently, I have it as Niccolo grilling Az on whether Az has any secrets Niccolo should know about and being too cynical to believe Az saying that he has none, starts listing off types of dirty secrets and notices Az tenses up slightly when he gets to "You're an invert."

Niccolo stays close friends with Az because Niccolo doesn't really care about homosexuality (well, at least they'll never fight over who gets to make the moves on a hot chick first), or possibly even likes the existence of the taboo because it's good for blackmail. So Niccolo can't be too cruel in the process of finding out. Az stays loyal to Niccolo. It never really occurs to Az that Niccolo agrees to keep his secret for not entirely nice reasons.

One option might be to have Az repeatedly turn women down. Nic could try to set Az up with a girl, and Az says he's not interested. Just some small hints here and there that assorted girls "aren't his type." He could also catch Az looking at a guy's ass.

Lots of little clues can very easily make it obvious. And then one day, Nic can just casually ask, "So you're gay, right?"

Have Nick borrow Az's computer, and accidentally stumble upon his Porn Stash, whether by way of uncleared history or opening the wrong folder set to thumbnail preview.

There's an easier way: a chance overheard converstation between what are strangers to him (waiting in line for something -tickets, maybe-, in a restaurant, whatever)... and one of them is Az's ex (or, wanted-to-be-partner) from High School. A few details added with what he already knows, and Nick can draw conclusions.

That works. It probably would strike Niccolo as a bit odd that he can't seem to get his friend to get into anything resembling an active conversation about the parts of women he likes. Az has very little opinion on what makes a girl look good (assuming she isn't terribly deformed or dressed like she rolled in a pig sty) so he just kind of smiles and nods on the subject minus when it comes time to turn down any attempts at matchmaking.

The setting is a pseudo-1920s fantasy land. Though I'm not sure if Az looks at porn in the first place. Though he does attempt to nonchalantly look at the other guys in the locker room.

Hmm, yeah, that could work.

Maybe Niccolo will initially think Az is just a bit of a prude or one of those sentimental types holding out for "the one" since he seems to have no interest in acquiring girls in large quantities (Niccolo imagines himself a casanova, though it generally doesn't play out that way). Then he starts noticing Az's Male Gaze is going different places. Then he starts wondering if Az's romantic aspirations don't involve the female sex at all.

Though since Niccolo is in the business of threatening people to get what he wants, perhaps he needs something from a guy who he doesn't know was romantically involved with Az. To try to get out of whatever Niccolo has thought up to do to him, he might blurt out for Az to help him out and is annoyed Az is being completely disloyal to someone he didn't have a bad break-up with... Heaping on disproportional retribution on someone he did have a bad break-up with. It's a bit vague how Az came to be single at the moment.