oh rats

At least rats are honest about their nature.  Maybe it's liberating being able to run around nude in the sewers. 

"wallowing in shit
they both do"

These lines are awkward and maybe a bit on the bludgeoning side.  I think it probably needs to be said, but with a bit more subtlety.  Also, what would you think about changing the last stanza just a bit, to:

Or in the dark shadows
of a backalley while the drunks are
collapsing

Since they don't really wait for it, do they? 

Rats are partial to merlot -- it sounds posh but it's easier to pronounce than most of those terribly confusing foreign words, and it doesn't take an educated palate to slosh it down with greasy eggs.