Be mindful of those around you.
Be straight-forward, warm, and polite, and don't try to put on an act or drop cheesy pick up lines.
Talking about sex doesn't have to be super serious.
Most women want to feel like sex is your idea and that you are taking the lead.
Does the same happen when a woman masturbates? As the body is excited and turned on, the breath becomes more urgent and rapid.
If he tries to make a move on her after using the nice guy approach, he will then likely get rejected.