It appears to be a regional, AmE usage: 

***[Muckle][1]***:

> To grab on to an object, usually with a great deal of force. May also be used figuratively to indicate a strong attraction for an object or person. Ex: "When I saw her down the bar, I muckled right on to her." ***Origin: Downeast Maine.*** 

(Online slang dictionary)

[Muckle][2]

>  (US, dialectal) To latch onto something with the mouth.

> - 1954, Elizabeth Ogilvie, The Dawning of the Day‎[1], page 199:
And how'd she get such a holt on you, Terence Campion, let alone the way she's muckled onto those Bennetts?

(Wiktionary)
  [1]: http://onlineslangdictionary.com/meaning-definition-of/muckle
  [2]: https://en.m.wiktionary.org/wiki/muckle