It's when your fucking a girl from behind when she is on all fours. Then you stick a hot dog in her ass at the same time pulling your penis out of her vagina, then cramming your penis down her throat. She will instinctively gag thus shooting the hot dog out of her ass into the awaiting hot dog bun.
While having sex with my girlfriend I became hungry. Soon she thougt she was being DP'd. To her suprise she was just used as a Ball Park Betty Rump Roaster.