It is true that anyone can be ganting on something at anytime however the true use of the word is in the context of a description of a highly unatractive female.
Person 1: What are you doing tonight?
Person 2: Nothin
Person 1: Oh thats cool, big day tomorrow?
Person 2: Yes
Person 1: What do you have to do?
Person 2: Nothin
Person 1: You are really "Ganting" me right now.
Person 2: OK
Today my coworkers and I were Gatting and placing bets on the over/under for how many people will be annoying assholes and "Reply-All" to the latest email that was sent to the entire company.