The artist Amanda Palmer popularized the term in her hit song “Map of Tasmania.” The lyrics include the following popular verses:
Walking down the street, I’m the lady showing off my map of Tasmania.
Soft and sweet and shaped like a triangle
Some girls want no shape and they shave it all
That's so whacky, hurts with the stubble
Walking round, look like an eight year old
I say grow that shit like a jungle
Give 'em something strong to hold onto
Let it fly in the open wind
If it get too bushy you can trim
The word originates in from the Irish 'maith' which means good. Caillín maith meaning 'good girl' became a way of refering to your girl friend.
Over the years the word changed so it was simply 'mot', which became used by lower class Dubliners.
Now is widely used to refer to all women of similar ages and not just girlfriends.
Me mots coming over later to give us a wank.