a guy that doesn't care if a girl is single or not. He will try to go for her, He usually talks to four plus girls at a time. He is a horn dog. He is a big flirt. Does whatever it takes to get with a girl.
When one of your mates or your girlfriend tells a story that he/she reckons is funny and everyone knows it's not going to be, that feeling you get of being embarassed or ashamed of your mate/girlfriend is Yarson.