Hi there,
Your first question is probably "What are all those stupid First - stories?" Okay, I mean the question after "Where is the sex?" and "Could you point me to the GOOD authors?"
My "First<--->" stories are a teen guy meets a teen gal and they experience their first time. A best introduction is my mega-popular story "First Cake". You might also try "First Accident" and "It's Just Biology".
I like the underdog or ignored guy who suddenly is discovered by the girl(s). "Floor Exercises" is a good and popular example. "Hole in Four" is another.
Other popular stories include "If You Can Catch Us...", "Out of Time", and "1984"