You know how to talk already. You just might not know how to talk dirty during sex. Talking dirty during sex is a big turn on for a lot of people but many are afraid to try it. They are afraid they'll do it wrong or that their partner will be offended or laugh at them. Like most other things you try in bed, you might want to give your partner a head's up before using vulgar words to spice things up.
To be perfectly honest it's all going to be trial and error. Everybody's different and the things that drive one person wild might do nothing for another. However, I have some suggestions you can start your homework with.
In my opinion, dirty talk should begin well before sex. Send your lover naughty texts or emails, describing what you'd like to do with him or what you are wearing. Whisper a sweet, naughty something in her ear while you are out shopping. In private conversations, casually express how much you enjoyed making love last night. It's like keeping the lines of sexual communication open in a hot, sexy way. Remember flirting? It's just flirting: stage two. Subtle innuendos fit right in. You don't need to start with vulgar words right off, you can begin by just having sexually charged conversations.
When you're ready to dive in you may want to start with compliments during sex, go with your feelings. Things like "Oooooh, I love fucking you" or "I love the way your cock feels inside me" or "your mouth is so beautiful I want to fuck it" might be good starting points. You can also say what you are feeling, being candid and emotional. "It feels so good when you lick my balls" or "my pussy's so wet" can fit right in. Another approach is to ask for what you want, again, with deep emotion. "Oh, yeah, suck it, suck it harder!" or "I want to feel your cock inside me right now!" are good examples of this. These are only examples, be creative and be genuine. Express your feelings without inhibitions. Talk from your tingling genitals.
You can slowly work your way up to more taboo language and involve role-playing. This is where calling each other raunchy names might come in. A man calling his partner a whore or a dirty little slut during sex is generally playing a role. Sometimes, this can serve as verbal encouragement for her to role-play, too. She can play the role of the "dirty little slut" which might make both partners more comfortable having wild monkey sex. After all, do you think of having anal sex with Jessica (mother of three, accountant) or do you fantasize about cornholing Jessica the wild slutty sex kitten?
Don't worry about sounding cheesy, out of context, pretty much all sex talk sounds cheesy. To increase your sex slang vocabulary you can read erotica (maybe together?) and even consult a slang dictionary.
A few of my favorite resources for sexy words are these:
Kylyssa is a freelance writer and a wanton, licentious, lascivious hedonist. She is passionate about sexuality, sensuality, and the First Amendment. You can read her strange and sexy blog at http://kylyssa.blogspot.com/