Noun. A code, used largely amongst drunk males, chiefly in the presence of females, or in the presence of people who would deem its meaning inappropriate (e.g: parents, priests, her parents). It originates from the old nursery rhyme: "nic nac paddywhack, give a dog a bone," and refers to the act of using a particularly unattractive person for non-commital sexual relations, with little to no intent of actually forming a long-term relationship.
Altar boy 1(low voice)>"So! You and Sarah huh?"
Altar boy 2(whilst motioning in the direction of the priest, who peers menacingly up from his sermon, and in a lower voice)> "Nic nac paddywhack"