An Unexpected Call

My girlfriend studies in another city. Usually, we both watch a series in the evening and text about it, stuff like that. One evening a week she goes out with friends. I wish her a fun night and don't suspect a thing. After a few hours, I text to see how she's doing. She replies that she's enjoying herself, dancing with a hot guy. I'm perplexed and horny at the same time, because this is a fantasy of mine and she knows about it! So I just reply, 'Sure, have fun', slightly anxious about what might happen next.
An hour later she calls me, which is unusual, because we neither of us like chatting over the phone. I pick up and start to talk but she doesn't reply. All I can hear is heavy breathing and kissing. Then the sound of unzipping. Followed by what I assume is the sound of her sucking his cock. Later, I hear her moan as he eats her pussy, before they go over to passionate fucking. I sit and listen to the whole thing. And I love it.