shasterbate 

shitting while masterbating

person number 1: "oh wow Justin the football player, takes a long time in the bathroom"
person number 2: "hes probably masturbating while he shits"
person number 1: "haha, Justin shasterbates"
person number 2: "hahahaha thats clever. shasterbate!"

shasterbate by shexcelent December 1, 2009

shasturbate 

The act of masturbating while defecating.

I was in such a rush this morning that I was forced to shasturbate,.

shasturbate by vink pink February 10, 2005

Smashterbate 

Masterbating while extremely intoxicated

Smashterbate - I don't remember smashterbating last night becuase I blacked out, but I'm sure I enjoyed myself

Smashterbate by RP DP April 22, 2011

shaturbate 

To shit and masturbate at the same time

I was sitting on the toilet, and I decided to shaturbate to this picture of Jenny

shaturbate by Poloshirts64 May 7, 2014

Shiterbate 

To go to the restroom, informing everyone you intend to take a shit, and remain in the restroom for an extended period of time while actually masterbating

Scott: Where is Kevin?
Andy: Oh he is in the bathroom, has been for 20 minutes, said he was taking a shit.
Scott: Oh, he must be going to shiterbate.

Shiterbate by Nazgul4591 November 1, 2009

smashterbate 

To pleasure oneself until pain sets in

Kelly smashterbated herself to the thought of other girls smashterbating.

smashterbate by Requiett January 3, 2005

shitsterbate 

to masturbate on the toilet while taking a shit

there are some good porn mags in the bathroom I couldn't resist getting my shitsterbate on just now.

shitsterbate by james___ March 20, 2008