There are many euphemisms (polite ways of not mentioning what you are really talking about) for referencing this subject.
Let's start with the basic one: "He is talking dirty" "He talks dirty". You don't say "dirty talks" in plural - it's talking dirty, in general.
If he uses uncouth language (direct references to sexual acts, or even simply generally swearing, using obscenities) when speaking, you would say "he has a filthy mouth" or "filty tongue". Or of it, "I don't want to listen to such filth!"
But there's really no need for euphemisms if you just want to say, "Guys like to talk sex" (or "talk about sex"). Although I think it very sexist to say that, as I have it on good authority that women talk sex more than men do.
Someone who has a filthy mouth or who talks dirty or speaks of sex is not necessarily perverted, so be careful of that one! A pervert is someone who is actually involved, even if only by observation, in sexual acts that are taboo in that society. Perversions are not always perversions in other societies, by the way, so be very careful in this accusation. Reserve it for kiddie-porn or bestiality. Even rape is not a perversion, although it may be abominable, it's not really perverted.
I hope I've helped a little?
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