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.*** 


  [1]: http://onlineslangdictionary.com/meaning-definition-of/muckle