I guess this applies to in school but mostly outside of school. Do you just get at the one girl you want? ("I wanna talk to you" seems a little too sudden) Or do you talk to both then somehow give your number to only one? (how do you manage that?)
Dinner ran three hours. She laughed at everything. You walked her to her car thinking this one's locked in.
Then: nothing. Two texts. No reply. What happened?
You did what most men do on a great date. You filled every silence, answered every question, and left her with nothing to wonder about. No mystery. Nothing to sit with when she got home.
Rule 3 of the "22 Rules" changes the ending: tell her a little, hold back the rest, and let her imagination do the chasing. The ghosting stops too.