Okay, so Classic Proto maybe unfuckable...
But you can’t convince me that RubySpears Proto isn’t. That man definitely fucks!
Now whether or not he likes getting pegged or doing the pegging is beyond me. But either way, he definitely fucks.
i may not be able to convince you, and that is fine. some people can live in blissful ignorance. but i must inform you the fact that you are wrong, this man has never seen a single sex in all his life.
if the prototype robot that light and wily was working on before wily threw a tanty was the basic bitch default version of protoman, then it turns out his primary objective is not to get laid but to start shit and cause problems on purpose. which is honestly a pretty admirable start of life and provides a consistent character arc through the series. but let's say that's not him, which is honestly a viable theory, and let's look at the protoman in the now as he is.
and as he is? well, he's a fucking virgin. in the "emphasizes the word virgin" way, not "a virgin who fucks" way, which is an oxymoron. he talks like he does, acts like he does, jokes about it like he does, he'd probably tell you about how he lost his virginity in a wacky over-the-top way. and eventually you'd realize he doesn't actually know what sex is and he's talking about the first extra special weapon he equipped. which wasn't a titty or a penis, btw. the first time we see him get an extra weapon on-screen, it's the super arm, and you try fucking with that and there's gonna be a fistful of problems.
he's one of those goobers who thinks he knows all about sex because he's read a bunch of hentai and so that means he's an honorary Fuck Master just waiting to blossom, and then starts quipping witty double-entendres with a seductive voice layering the attitude of a man who thinks he's fucked in spirit, but the moment you show him a single ass he just curls up and starts quivering. and you can't fuck that.