OP - The idea of the exchange (and someone correct me if I'm wrong because I haven't actually run one personally) is that you get to choose the prompt you fill without knowing who it belongs to. So if you don't write erotica, that's fine. The idea is to pair the prompt to the best filler.

And also the idea is that every prompt gets filled because you do an even exchange. So everyone who prompts for it has to write.

Hopefully that makes you feel a bit better. :)