When you are standing quite a distance away from your boo, possible behind an object which leaves you partially hidden, and you want to let them know you are thinking of them, you wave from that distance hoping they will see you. While you are engaging in the waving act, you may wish to send them a few air hugs and wind pecks, which is also part of the Peak-a-boo package.
It can be used as a noun, adjective or a verb
*note: please make sure the your Peak-a-boos are received by your boo and not a random person. There have been cases of Peak-a-boos being lost in transmission :)
"awww... they're such a Peak-a-booers"
"honey... i am Peak-a-booing you from a distance. with love"
"wow... that gorgeous guy just got Peak-a-booed by that girl over there"