Half done trans woman means usually a very pretty chick with a dick. They make fun of the older/ less attractive ones, but that is more in a laughing at the other kind of way.

Of course Bobcat Goldthwait said it best:

Damn it, can't find a video of it. Basically it's a macho dude beating the s*** out of gay dude and the running monologue the macho dude has going in his head runs through: I hate you. I hate you. I hate you. I want to f*** you.

But not with the pretty ones. So they might spend a couple moments ogling the top half and then their eyes wander down and see a bulge. At this moment they have some serious internal problems. They were getting horny and it ends up being a guy. And the better looking, the more they freak out. They could very easily attempt to pick this one up at a bar and get fooled.

I'm pretty sure this is where the gay panic defense comes in.

https://en.m.wikipedia.org/wiki/Gay_panic_defense