When an uncircumcised man slides his foreskin over top of another mans circumsisedpenis and proceeds to jack the man off with his foreskin. Its like the tight sleeve fitment of stove pipes, hence the name stove piping!
Man, Pasquallys foreskin is a real tight fit!! He could barely roll his foreskin over my cock! It was just like we were stove piping in a wood stove!