First of all, you shouldn’t be worried about what to be calling him, just go with whatever feels the most natural. If it feels totally awkward for you to call him “daddy” or “sir” or whatever you think he wants to hear simply because you think that’s what he wants to hear, that is only going to ruin the mood for both of you. I can tell you for sure that hearing you moan his name or telling him how wet he makes you or how much you wish he was there to touch you is going to turn him on much more than you pretending to call him something that neither of you are into.
That being said, I know that sometimes it can be a bit difficult to get into the swing of things, especially with phone sex. You don’t want to sound like an idiot but you shouldn’t be so worried about how you sound that you don’t enjoy yourself. If you’re in a relationship with someone, you shouldn’t be afraid to deal with a bit of awkwardness when trying something new. Focus on letting your partner know what you’re feeling and thinking about. If there’s something about him that really turns you on, tell him that. If there’s something he calls you that turns you on, tell him that, too. Let him know what you’d like to be doing to him, let him know how you’re touching yourself at the time, how much more you’d enjoy him touching you, etc.
There isn’t any kind of science to it, that’s for sure. Maybe he thinks he’s terrible at phone sex and thinks you sound like a pro. It’s good that you’re open to trying to new things especially with long distance, things can be rough and I wish you lots of amazing phone sex orgasms.
-teagan