When one has sperm up the butt then when he/she farts and it makes a white cloud. Commonly seen in cartoon porn.
"Dafuq is that white cloud there for?" -Guy 1
"I just had a little bit of a Ghast Blast" -Guy 2
"I'm just gonna walk away now..." -Guy 1
"I just had a little bit of a Ghast Blast" -Guy 2
"I'm just gonna walk away now..." -Guy 1
by Jhon Gewer January 20, 2014