Kind of like “Spidey Sense” but instead you’re sensing that someone, somewhere, usually in a group chat you’re in you haven’t checked it’s a little while, are talking dirty without you.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.