Slang for a male request of oral sex, either towards another male in a sarcastic "shut the fuck up" way or in respect to previous events, however not commonly a serious request to a female.
Example: "Man, wanna' come play poker?"
"No, huff my dong."
"How was your night with Shaundra last night?"
"Good, man."
"She huff your dong?"
"Twice."
Simply another way of saying "suck mymanhood", because you can never have too many methods of parlaying this fine gesture of true respect to your fellow man.