Self pleasuring involving a basting brush.
We realised he was masterbasting when we kept finding the basting brush in his room.
When you come back to the family's house for Thanksgiving and you leave your vibrator at home. Grab that turkey baster and go to TOWN!
Holy S**t! Masterbasting with this turkey gravy is drivin' me crazyyyy!
Someone who is really good at using a turkey baster
Give me that turkey baster
Here, woah bro your a masterbaster
The act of basting something with ejaculate.
Dustin masterbastes his turkeys on Thanksgiving, why would one do such a thing?