Was it easy for Holden to communicate with girls? Was a girl's duty important for him? Can we call him a heartbreaker?
Holden has a hard time connecting with anyone, including girls, because he is a cynic and because he refuses to grow up. Throughout the story you notice how he comes quite close to establish a relationship and each time he is close, he expands back-this is what they call the "rubber band syndrome". Most of the information about sex that Holden wants to know about is through either Stadlater (the real Heartbreaker from school), or through Carl, his student advisor.
The women whom he makes contact with in the story, the prostitute Sunny, the pretty girl Sally and others were more like attempts for a bond. He even called Sally "stupid".
The other one is Jane, whom he had met a while back (doesn't appear in the story) and seems to be the only connection he actually made in his life with a woman BUT- we cannot swear by this because Holden's view of things is convoluted, and this may have just been a friend whom he felt safe with in younger years.