A sexual act between a male and a female.

This act begins with the female giving a hearty blowjob to the male. Once the blowjob is complete, the male ejaculates into the female's mouth. Instantly after the aforementioned ejaculation, the male also urinates into the females mouth hole. This maneuver is best done when the male is slightly dehydrated, as to make his urine more of a yellowish hue.

After the semen and urine are in the female's mouth, she keeps her lips around the male's penis and proceeds to slosh and motorboat the mixture around the males penis. Resulting in a feeling that can only be compared with sticking your penis in a warm bowl of marshmallow cream.
Guy 1: Dude! last night I got my girlfriend to give me another mustard wash!

Guy 2: You seriously need to pee before you get head next time.
by george133 June 14, 2011
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