When a chick gives a guy a RimJob (RJ), moves slightly and nibbles/licks giving the Gooch some Action (GA), and then moves slightly again to give the guy a BlowJob (BJ). These three thing together in that order are called giving someone "the initials."
My girlfriend came over last night and gave me the initials. First she licked my ass, then played with my gooch, and finally she gave me a blowjob.
Initially, this wasn't a definition.
No, wrong way to use it. Initials can be like I.S or something. Maybe Candice Rhydon can be shortened to C.R.
The first letter of a name, add it when referring to a long name to shorten it. Initials are, well.. the first letter of each part of your name. D.N, or C.R