You gave her dog a snausage!

What are you up to guys?

In order to pick up good expressions, I've been watching a movie 'Liar Liar.'

Jim Carey, attorney, acts weird in court as he was unable to lie.
Against his will, he even provokes his own witness into admitting
that he and the client had an affair.

These are what he said.

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You slammed her !
You dunked her donuts !
You gave her dog a "snausage" !
You stuffed her like a Thanksgiving turkey !

All right, it's true, okay !
l humped her brains out !
There ! Now you happy ?

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From the context, I could easily notice that
almost all those expressions refer to the act of getting laid.

But the one 'give her dog a snausage' was a bit puzzling.

I looked up the dictionary to find out it means 'dog treats'.
Then, 'give her dog a snausage', I guess, means that
'give something to eat to her dog.'

How come it gets to mean 'having sex'?

And do those expressions sound all familiar to native speakers
- slam her, dunk her donuts, give her dog a snausage, and hump her brains out?

The movie is intended to make people laugh,
and I can't help but wonder if some expressions are used almost only in the film and barely used in the real world.