tough titty said the kitty

Chosen for the rhyme. The image is of a kitten suckling at the mother cat's teat, hence the references to milk in the extended variants.

tough titty said the kitty

1. (humorous) Synonym of tough titty (“hard luck; too bad”)

• Sometimes further elaborated into various phrases involving milk: "tough titty said the kitty..."
  • but the milk sure tastes good
  • but the milk's still good
  • but the milk's damn good
  • but the milk tastes fine
  • when the milk went dry
  • when the milk wouldn't run; etc.
  • that spilled the milk