pacman
While hitting a female doggystyle, grab her ass cheeks and stretch them apart such that her asshole stretches into a horizontal line.  One must then release the cheeks so that the roundness of the asshole is preserved.  By doing this over and over again at a steady pace, the asshole looks to be mocking our favorite Nintendo character from decades earlier.
"Yo man, I was hitting my girlfriend doggystyle and pacman'ing the shit out of her...she absolutely loved it!"