Stands for "shitting my pants, jacking off uncontrollably." Used in situations where you have no idea how to react, so you lose control of your bowels and begin to unwittingly masturbate to no end. It is a similar reaction to having your head explode. Most often used after comments in social networking sites and in text messages.
I can't believe it's not butter! #SMPJOU
by Hashtagharry May 21, 2013