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.
af Ryan Huie 13. februar 2005
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.
af Wes 14. februar 2005