1
general::
Contribute money to a pool or reserve, as in I can't make a big donation this year, but I'm willing to feed the kitty something. This term, originating in gambling, incorporates a pun, since kitty can mean ‘‘cat" as well as "pool." [Late 1800s]
American Heritage Idioms
2
general::
Phrase(s): feed the kitty
Fig. to contribute money. (A kitty here is a small collection of money.) • Please feed the kitty. Make a contribution to help sick children. • Come on, Bill. Feed the kitty. You can afford a dollar for a good cause.
McGrawhill's American Idioms And Phrasal Verbs