How to confront people for disrespecting gender without hostility

So I've talked about this a few times, mostly in that vent thread. There is a guy I work with at my night job who is several years younger than me, and very queer friendly, definitely no machismo there, I'm surprised (so is everyone else) he's straight. He is the only one who knows I am trans at that job. I specifically told him because I thought he would be cool about it, and we're sorta friends. But, he uses a lot of endearments and constantly calls me things like girl and girlfriend and ma'am blah blah blah even though he knows. Recently he said something really offensive (not meaning to I don't think) that made it clear he didn't understand me at all and is having a hard time thinking of me as male or even understanding what I mean when I tell him I'm trans. He still acts like I'm a lesbian basically and was asking me shit like who is the guy in my relationship. (I am with a clearly feminine woman and he knows this.) and have I ever thought about being "straight again"? I've pretty much given up on being friendly with him since then.

Well, today I closed with him and he called me a female endearment a total of 3 times (less than usual actually). I finally snapped on the last one, and this was the first time I've really confronted him. (Actually, I've never confronted anyone about misgendering me [and I'm not even talking pronouns or birth names. Just asking not to be called anything female specific that is not directly relevant to the conversation or necessary for clarity], except my fiancee, and never sober.)

I've been wanting to confront him for a long time but I was worried I wouldn't be able to contain myself and I would be overly hostile or get upset. Actually I was going to post a thread BEFORE asking about how to nicely tell someone not to call you things like that, but I couldn't take it any longer. I said to him, maybe yelled, "If you call me girl one more time we are going to have a (fucking? not sure if I said fucking or not, but I'd be surprised if I didn't. I was just seeing all red.) problem." to which he immediately said it again. He later said he thought I was joking at first. I told him I was serious and it was really (fucking again? Not sure. lol) disrespectful to talk to me like that when he knows I am trans. He said basically "Jeez okay I know you're trans! Could you hand me (that thing, forget what)?" To which I said "Get your own shit! How many times do I have to put up with your bullshit?" and started very calmly (or maybe the exact opposite of that) banging around while doing dishes and giving him dirty looks for the next hour. Man, I was pissed, and this was exactly what I was afraid of. I can't confront someone nicely. I just bottle things up for weeks or months and play the martyr with myself saying look at all this shit I tolerate, then finally explode in self-righteous fury.

Anyway, I felt bad for being so harsh, but he did apologize later and has started calling me dude or bud. I know I shouldn't confront people angrily, but he is actually really dumb so I think he needed to be told extremely clearly and see how much it actually affected me. I just wish people like him would stop throwing around gender specific terms so much in general. I mean, sure I'd rather be called dude or bud, but what is wrong with just using peoples' names?

Anyway again I (I think this is the most disconnected/incoherent thing I've ever written lol), how SHOULD I have handled that if I wanted to come off as not such an asshole? Like I said, in this case it seems to have worked, but I can see that ending badly in other situations. Like, it would end up with them just thinking I am insane and have anger management issues.

What would be a nice little phrase I can have handy? Without sounding too dramatic and not trying to make anyone feel bad, but getting my point across very clearly and making them understand how I feel?