Momentarily after having a large bowel movement, the need to return to the restroom to produce another, usually smaller one (in some rare instances the aftershock can be larger).
That little bit of cum that escapes out of the penis approximately 10 minutes after set stimulation, i.e. blow job, hand job, or the preferable way, sex.
Don't get dressed just yet, I still need to aftershock.
When a girl has her period, then it goes away for a day, then returns the next day because there was left over blood.
Girl 1: Shit, you gotta tampon?
Girl 2: I thought your period ended two days ago..
Girl 1: I thought so to, but I got that damn aftershock.
Girl 2: Ohh....