You wake up near your girlfriend. She is still tired but she wants to do something with you today: maybe hang out with some friends? While she talks, you cannot contain a disgusting expression on your face, because of her morning breath. Totally awful!
She notices that and since she is very touchy, she gets mad at you and starts to breathes directly on your nose and mouth, as revenge.
You shouldn't be so rude with her. Now smell her disgusting unwashed mouth!