how do you explain a plumbing vent to a millennial

[Tom Raymond]

You ask them if they've ever short gunned a beer...

[mlparham]

Place a straw in your Red Bull. Cover the top of the straw with your thumb then remove the straw from the can. Nothing happens. Now remove your thumb from the straw. The straw now drains, just like your plumbing.

[Tom Raymond]

This little joke is based on a true story.

When presented with needing to replace a pipe boot, the lady of the house could not grasp the need for a vent. That's when her man offered the "it's just like a shotgun hole in a beer can" analogy. Concept grasped.

Kids these days...