A sponx is a sex move in which the male inserts a box of crayons into his anus whilst in a robot costume. During this fiasco, the woman dumps a wocky slush down her throat and regurgitates it on his nipples*

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.