The abbreviation of the phrase Mental Shift.
An M-Shift, or mental shift, is a therianthrope
-related occurence wherein a therian
feels their mindset, or current mentality, becomes that of their phenotype
, or animal.
An M-Shift may be brought upon by many environmental and/or sensory factors, such as weather, certain people, smell, sound, taste, etc.
How intensely an m-shift is felt, and how long they last, vary from therian to therian.
See also: P-Shift
, Astral Shift
, Suntherian Shift
, and Phantom Limbs
I had an M-Shift about a week back; my first in quite some time.