I Don't Like Coughee

I have a find hidden objects free online curious disease in vitamins for senior dogs which I cough spasmodically late at night and early in the morning. In between these times I vacillate between totally vagued out and pretend normalcy. So I just bought some LemSip cough mixture that smells like low grade disinfectant, which I am hoping will provide an instant cure. The past few days have been spent packing up all the stuff in M's mothers house. I have managed to subdue M to the point where he only refers to his mother as 'Old Manky' when not in her immediate presence. This is a good thing. But it has left me pondering Mank.

A curiously expressive word. Indeed, I have been, as I said, pondering its heritage. I can only conclude that it's a collision of mould and stank, however I remained slightly stymied as stank is obviously a past-tense word, i.e.
"Her refrigerator stank."
But mank is an obvious improvement on stank as it can be applied in both the present and the past tenses.
"Her refrigerator is mank."
"Her refrigerator was mank."
(...and it has even more flexibility, as in both of the previous statements, the letter 'y' could have been added to make mank into manky and the meaning would have stayed the same.)

Besides being breathless with awe at all the ways M manages to weave the word mank into daily life, I am intrigued by its very existence. I do recall a friend of mine using it back when I was in about Year 8. I googled mank and ended up with lots of references to mankkind, but on googling manky, I found this. Does anyone else use mank? It's not listed in WordMap - but then again, it's probably not a regionalism.