when a girl is fucking you while she has a yeast infection and smears that goop all over your shit.
yo i ran into some lap butter the other night, it was horrible.
by DonSlappy November 02, 2011
a clear yet cloudy liquid of great viscosity, that is excreated from the lap of a suitably excited woman.
her lapbutter made his knee very difficult to balance on, the floor was also covered.
by stoph1983 April 28, 2007
the juice that flows forth from an excited woman
as john bounced janet on his knee he could detect a slight residue of lap butter seeping through his trouser leg
by stopherer May 11, 2008