Shitty fucking is like titty fucking, but before you proceed to push the tits together and titty fuck them, you shit in the cleavage. Once you are done you make your partner lick the shit off you dick.
Titties that are right for shitty fucking are called shitties.
"Dude Eric how was Becky in bed."
"Awesome, her shitties were perfect. I shitty fucked her all night long. Shitty fucking is the best feeling in the world. I still have some shit left over on my dick though. She doesn't have a very big tongue. It was suprising too because my dick is only two inches long when erect."