Nope, that’s not a typo (even though there’s lot of red underlining under it while I’m writing it). Masculate is exactly what you’re imagining – the opposite of emasculate. So it means to make something more masculine. You can also say that you’re masculinising something (which sounds made up but really isn't).

I came across this because I was investigating whether there’s a female equivalent of ‘emasculate’ (as in to deprive a man of his male role or identity, rather than the more literal definition of castration). Turns out there isn’t. *shakes fist at patriarchy*