Knockin' Noggins
When one or males make contact with the heads of their penises. Can often be played as a game similar to jousting.
Hey man, as long as we have our pants off... We might as well be Knockin' Noggins.
Knockin noggins
To catch fish
We went down to the river with the boat, a fishin pole and a case of cold ones, and proceeded to knockin noggins on them big ol flounder like they was goin outta style.