noun: urine emitted from a
woman's urethra, which rather than successfully reaching the toilet, instead trickles downward and enters that
woman's own vagina (usually by
accident).
verb: to get urine in one's own vagina while urinating (usually by accident).
Etymology: contraction of "vaginal backwash".
Connie tried to piss
lying down, but the last few drops didn't go far enough and vackwashed into her pussy.
Make sure to
douche after vackwashing or you'll get a yeast infection.