[kunai]

Tell the person to fuck off.

Okay, I may get many downvotes here, but this doesn't seem like the solution to the problem. Rudeness and insults are rudeness and insults. Cursing doesn't help the matter.

Inaction is not the solution either, but I'm sure there's a more mature way to handle things. Asking the party to leave politely is better than keeping your mouth shut, and it also seems better than cursing them out.

Of course, if they refuse to behave, then tell them the magic words.

Fuck off.

[mlent]

It probably depends on the person. With a guy who uses phrases like "because tits", "fuck off" might be the only thing that makes it through his thick skull.

[reeses]

Right. There are a number of attempts to generalize the terms of the discussion, but "because tits" guy is a specific wanker. It's OK to say things to this person precisely because of his specific behavior.