If this is the first time calling a phone sex line please leave your inhibitions behind. Don't be shy. Ask for what you want. There is no point in talking to a mature woman if what you really want is a conversation with a shemale. Be prepared to answer some questions when you first connect. The phone girl is not a mind reader and she needs some pointers on which way the conversation should go. It will save time and money if you just tell her what fantasy you would like to chat about. If you are not truthful right off the bat then she is going to lead you into a fantasy in which you have little interest. It is not her fault. It is yours. Remember, this is your dime and you get to call the shots. She is there to please you and help you live your fantasy. If the phone call starts going down a path that you don't like, gently bring it back. just say, "That is fascinating but what I really like to talk about is anal phone sex"
This really is all about you. It is one of the things that makes phone sex such a terrific hobby. Another is the fact that there are so many variations that they are impossible to list. Do not hesitate to ask for even the most esoteric of them. Nobody will laugh at you, instead they will do their best to hook you up with the right person so that you can live your dream. Just suppose that you would like to be the slave of a mistress who will sit on your face and smell her stinky ass. Not only possible, but a common request. Or, you have always wanted to fuck your sister. Now you can phone fuck her to your hearts content. The point being that there is nothing that is too far off the beaten path. What would truly be remarkable is if you could come up with a fetish no one has every heard about before. Before you try, consider the thousands who have gone before you. You have some stiff competition and the pun is intended. Phone sex is all about having fun. Don't lose sight of that fact. More pointedly, phone sex is all about you having fun. It is going to cost you some money but what the hell doesn't?
There is no need to go broke, however. Put a clock or timing devise where you can see it. I use a cheap egg timer. After talking to the operator you will know the per minute cost of the call. Estimate how much of your disposable income you can dispose off and set the egg timer accordingly. When it goes off make sure that you go off damn soon after that.