Bill D: No, no, it's two drunks on a train, which has just stopped.
"I say, is this Wembley?"
"No, it's Thursday."
"So am I; let's have a drink."

*

The example explained:

I will try to be concise.
You don't mean that; you mean repentant. [contrite]
You don't mean that; you mean shorten. [contract]
You don't mean that; you mean a silly machine. [contraption]
You don't mean that; you mean.... one purpose of a condom.