Taken from fastseduction.com:
pAImAI: pre-approach invitation male invitation
IOI : indicator of interest
pre-AI male AI, a semi-passive action or series of actions meant to inducement a chick to initiate an AI. A means to "pre-condition" a chick to initiate some form of non-verbal IOI before actually approaching her or doing an opener, usually the best IOI response to the structure being an AI. Essentially, it's a conscious male tactic (applied as if it was unconscious) that reverses the frame of a female unconscious "PU" tactic. 3 levels of pre-approach: 1.) No AI, walk into a room full of 100 chicks, randomly approach 10, randomly get 1 or 2 interested, perhaps not your best choice of chicks overall, but still better than 0. 2.) AI observation, walk into a room, observe the 10-20 chicks giving you AI, pick the 5 that interest you, spend half the time interacting with half as many chicks who've shown already shown interest (2 * 2 * 2 = 8x efficiency, with increased chick quality). And, with the more positive interactions, social proof for the other 95 chicks is enhanced, providing a method of roughly 10x better results. 3.) pAImAI+AI, walk into a room of 100 chicks, vibe intent everywhere and make presence known, observe chicks selectively (like a calm hunter), and cause 30 chicks to display clear IOIs or initiate significant AIs, approach the few (2-3) that REALLY interest you, knowing they are already highly interested, and that you've already displayed intent (10x AI efficiency * 1.5chicks * 2x interest = 30x efficiency, with MUCH increased chick quality). Overall, the first method is still better than what most guys do, so understanding pAImAI/AI structure, even without many PU skills under one's belt, increases opportunity at least 30x, if not 100x. Note: Some people migth refer to pAImAI as IAI ("Inducement to Approach Invitation"). Also, capitalization isn't strict on pAImAI - it can be types as paimai or PAIMAI, and pronounced "pie-my".