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1. mgg
Internet shorthand for Matthew Gray Gubler of Criminal Minds fame, often used on livejournal.

Occasionally written as em-gee-gee if the writer is feeling like a giggly fourteen year old girl.
In other news, MGG is a total GQMF.
2. MGG
Mammary gland Gyration... the act of tittyfucking
MGG is the same as tittyfucking, just a better way of saying it
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