The yellowish liquid that comes out from an upside down mustard bottle right before you squirt mustard onto a food item. Usually groans can be heard from the squirter indicating that mustard pee came out of the bottle instead of mustard.
by Cannibalporsche July 02, 2011
Mustard pee- That undesirable yellow liquid that comes out first when you are really expecting mustatd and usually makes your sandwich soggy
I made a sandwich in the middle of the night. I wasn't awake and forgot to shake the mustard so all he got was mustard pee that made his sandwich all soggy.
by IvyDana55 August 27, 2017
buy the domain for your travel vlog