Verb (I think)- A term commonly used when you see/visualize an extremly hot female (paris hilton) and you have the urge to stick your penis (cock) into a females patootie (pooper)
To do something so stupid, crazy and nonsensical, that normal people can't even understand what you were possibly thinking or how you could have done that.
Andy: Dude, I can't understand what you were thinking. Why would you set fire to your own porch?
Zach: Yeah, what was I thinking? I totally Pooped In the Shower on that one.