"Pounded like a rented gerbil" is a phrase used to describe disastrous events- usually painful financial setbacks.
As you can imagine, rented gerbils would be the unfortunate recipients of an especially rough and vigorous pounding experience, when compared with the more tender romantic encounters of privately owned gerbils. After all, you'll be returning the poor rodent right back to the rental office tomorrow, so why bother taking good care of it?
How'd it go for me at the blackjack tables last night? I got pounded like a rented gerbil, that's how! I dropped almost two grand! Fuck... that'll teach me to gamble with money I can't afford to lose.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.