Most women already talk dirty to their boyfriends without even realizing they are doing it. The simple words that come out of your mouth during sex are considered talking dirty. So there is very little to learn what you can learn is how to spice up your dirty talk.
The first and most important rule to learning how to talk dirty to a guy is not over doing it. If you are normally a quite woman who only swears when you slam you hand in the car door then your boyfriend will probably be turned off by vulgar words coming out of your mouth. Keeping that in mind you don