Top Definition
A. Mastebating while playing halo (1, 2 , or 3, because wars sux).
B. owning at halo.
C. being epic in any way, shape or form.
in-game kid: Hay Guyz im mastercheifing it up in my pants!
other kid: GROSS!

OMG i am SOOO mastercheifing *killionare*

im soooo mastercheifing *<<< chuck norris talking, of coarse*
by the cheifer November 25, 2010

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