The heffelfinger is a well used sex term. When the male is doing his partner from behind, preferrably doggy style, he will stick his index finger in her rectum. When there is a change of position, preferrably the male going on top, he will put the index finger into his partner's mouth.
When she asks if that was the finger in her rectum, the male replies, "Yes, thats the heffelfinger."
V. To destroy in an angry and reckless manner, usually the result of excessive alcohol consumption.
"My buddy polished off a 40 of Jack Daniels and heffelfingered the dash of my car lastnight, fuck that guy"
"I heffelfingered my truck around a pole this morning"
"You see that guy rage and heffelfinger that paper towel dispenser in the bathroom? that shit was intense!"