se poser des questions: to wonder, to doubt
tourner le dos à quelqu’un: to turn one’s back to somebody
loucher: to be crossed-eyed. In French is said: il louche = he is cross-eyed.
This is a pun on the expression “coucher le premier soir“. Coucher means to sleep, with the implication that it’s with somebody. However the characters being eyes, she doesn’t want to face him because she never “loucher” (be crossed-eyed) on the first date.
Bonne Saint-Valentin à tous!