Have you ever noticed the way a man's eyes glaze over when we start talking about ourselves in person? It's no different, and actually much worse, when it happens on these lines. Your caller might listen politely for a time before hanging up, but to really hold his attention, talk to him about HIM. Find out where he lives, what he's up to, what he looks like in detail... how he happens to be available for a phone sex call in the middle of the day - whatever comes up as long as the focus is HIM...
Ask specific questions... general questions sound insincere and remind him that he can hang up at any time... If you ask specific, targeted questions (questions based on thing's he's told you about himself), he will know that you're truly interested, and he will enjoy answering... For example:
WRONG WAY
Suppose your caller says he's in Montana. Most people's reply would be something like, "Oh really? Well I'm in _______________." This seems fine at first, but really think about it for a moment - you've just taken the focus off of him and put it on yourself. You can't see him, but his eyes have started to glaze over already :). Keep his attention by saying something about where HE is - maybe you've been there and liked it, maybe you know someone who lives there - maybe you've never been there and heard something funny about the place... give him a chance to tell you it's nice there, or maybe it's awful there but he's just there for work... ("Oh really? What do you do for work?")... Talking about his location is a nice ice-breaker and it gives him a chance to warm up to your voice, too.
A MUCH better reply to him saying he's in Montana might be, "Really? Montana? I hear it's really beautiful there - are there are a lot of mountains and areas that are still wild, like I'm picturing?" You never know - you could find out you have a Montana-loving outdoor enthusiast on the line who will tell you about his latest kayaking trip if you keep asking specific, interested questions. The main thing is, you're keeping the subject on HIM for as long as possible, lengthening your call and letting him know you're really interested in him in the process.
The above example could be applied to many different situations during your call. At all times, be listening for interesting things your caller might say about himself that you can ask for more about. A good rule of thumb is, if he bothers to mention it at these rates per minute, he probably wants to talk about it.

