Used to describe different levels or degrees of sexual experience. It is substituted for the base system, due to discrepancies amongst different people's definition of each base.
1 Star - Making out.
2 Stars - Boob touching, over or under the shirt.
3 Stars - Hand jobs, fingering, getting turkied
4 Stars - Oral sex, carpet munching, head.
5 Stars - Vaginal or anal intercourse.
The stars make communicating how your weekend went easier amongst friends.