When an 18-wheeler driver's wife cheats on him/her in an orgy with eighteen other men.
After accidentally driving through the wall, Larry found his wife in a Trucker's Dozen with the neighborhood watch.
69.
"That looks like a Biker's Dozen."
"You mean Baker's dozen?"
"Nope."
"How many is in a Biker's Dozen?"
"69."
"Nice."
Just as a Baker's Dozen historically refers to 13 (typically as bread rolls), A Chipper's Dozen refers to some number greater than that which was ordered, typically applied to Potato Cakes / Potato Scallops / Potato Fritters. In any such case, the customer will order and pay for some number of these fried delights and typically receive something like 1.3 to 1.5x that number. More typically this applies to an order less than a dozen, so it is more useful (though more cumbersome) to describe a "Chipper's half-dozen".
"Order 67! - 8 potato cakes."
"Yep, that's me."
"Yeah no worries. A few of these looked a bit puny so I threw in a couple more for ya."
"Thanks mate. Whoa thanks, there's like 10 in here or maybe more?"
"You're alright - just a standard Chipper's dozen."
A collection of sixteen of something
The hardware store sells a box of nails by the carpenter’s dozen.
Similar to a bakers dozen but instead of 13 bread rolls, you make 12 Carriers
I was like OMG, but then I realised I had the pwners dozen and roflestomped him