When you've wanked so much that you are sore, with very little left in the tank, but decide to wank once more in order to break your all time 24 hour record. Upon ejaculation, all that is present is a glistening bead in your japs eye - since you have no energy to propel it any further.

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.