To jack-off while defecating.

Usually done by Fat FFXI nerds who dont have time to complete each task seperately because they are too busy engaging in online parties and lvling up their ultra-uber Black mage.
"Jim is such a dirt-bag who Crapsterbates all the time"
"I was thinking of your mom while i crapsterbated"
by JdeL March 17, 2005
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the act of taking a crap while masterbating to save time
computer nerds do it most often while taking a break from WOW or halo or any other of that stupid shit
marvin took a break to crapsterbate after four solid hours of unreal tournament
by mr.salty May 15, 2006
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