look up any word, like dirty sanchez:
 
1.
To lock out or ask to leave a friend, relative or roommate so that one will have the privacy to whack off, use her vibrator, etc.

Similar to "sexile", except only one person is involved in the activity.
I'm going to mastergate my roomie and spank my monkey, to get rid of this ten day load I've built up.
by brownwings August 23, 2011
 
2.
Almost masterbate, but with a "gate" at the end to add a comic effect.
Don't make me mastergate all over you!
by The Frog Clinger January 16, 2008