Acronym, meaning 'Monotreme I'd Like To Fuck'. Refers to the popularity among the people of Australia and Papua New Guinea for these egg-laying mammals, particularly the echidna, a land creature covered from head to arse in spikes. Despite this potential obstacle, the echidna is prized for its attractive waddle, moist, winking chuff and easy, bohemian lifestyle.
Look! Over there! See that platypus scamping about in the stream, with its low metabolic rate and come-hither flippers? Now that's a monotreme I'd like to fuck, or if you will, a MILF, yes sir.