"How to Talk to Girls at Parties", Neil Gaiman

SS story collection (Fragile Things) - science fantasy
Two English teenage boys -- one is outgoing, the other, the narrator, is shy about talking to girls – head off to a party, but they forget to bring the directions. They find a party, but girl they know isn't there. The girl who meets them at the door is very beautiful. Turns out it's a different party entirely, and the girls at the party are quite different indeed.

A charming story. Gaiman wisely doesn't try to explain or describe things entirely, and that helps to make the story work.