It is illegal for a pool-room employee to shoot behind the back. Certain females are encouraged to shoot behind their backs, however. This is not sexism. OK, it is sexism. No sitting on tables, setting drinks on tables, or otherwise abusing the equipment.
Violators have the right to a trial by a jury of whoever wants to see a lynching.
No twirling of cues, even if you are Tom Cruise, or a known cheerleader. Playing pool for money is encouraged, however. Profanity is encouraged in moderation, when appropriate. Sometimes profanity is mandatory.