That means youre whipped. She did good with you..
If a guy tells his friends that his girlfriend is quality, he means that she is a great girlfriend.
it means he want to show off to his friends he has a girlfriend
He already considers you as his girlfriend, or he's just bragging to his friends.
Then, I'd imagine, you're friends with that guy. It doesn't necessarily mean he's into you, he's probably just social.
you can tell him, or his girlfriend if you are friends with her
It doesn't mean anything bad. She loves them because they are her friends and is not afraid to tell them that. There really is no need to worry about it, it doesn't mean that she is being unfaithful to you.
Asking for a date
That means that he wants to go all the way with you or he wants you to be his girlfriend
It shouldn't be if the guy loves her back.
Cheating
Flip your hair and laugh with friends.
ask him, or ask his friends