A person who is a great flirt and knows how to work their magic on people.
Plays people and knows how to get their own way when sex or any sort of sexual relationship is involved.
Sammy's never know when to shut up and will flirt with anything they see potential sexual contact with. They also tend to be pretty damn funny and you either love them or you hate them.
Most of them are pricks but they're lovable ones.
A 'Sammy' can refer to a male or female.