"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.