A Behind Was Left at the End of the Play

At a play as funny as
Campfire cowboys eating beans,
I laughed off my duff,
As others did theirs.
Fortunately, the management saved all the duffs
In Lost and Found.
Can you identify yours, they asked,
When I came to claim mine.
It’s the one that’s self-conscious
I said,
When it passes a full-length mirror.
They’re all like that, the manager said,
Go and take the one you like.
So I chose a perky number
With dimpled cheeks.