When one slaps his ejaculated penis in another's face smearing cum everywhere.
Dude, I totally gave your sister a sloppy milky slap last night.
by Ryan Huie February 13, 2005
1 more definition
The act of slapping one in the mouth with a penis after the mouth has been filled with ejaculate.
Randy's leg looks like somebody just gave it a milky slap.
by Wes February 14, 2005