How to approach a girl already on the dance floor?

in a club, how do you start dancing with a girl already on the floor?

what happen if her girl friends are dancing with her, how can a guy dive into this situation?How to approach a girl already on the dance floor?
Slap her on the booty and say ';Watch that big o' thang';. Every girl loves that.How to approach a girl already on the dance floor?
Just start dancing. Most girls are just dancing and don't mind if someone starts dancing with them. Just don't touch her. Some guys think if they want to dance with a girl you are just to put your arms around her like you know her. Just dance.



If she isn't interested she'll turn around or move a bit. Most people dance one dance and move on anyway.