The act of your significant other latching onto your face with his or her mouth and moving it around your face, creating a trail of saliva similar to one that a slug would make.
Brooke gave me a slug job last night; I think I'm in love.
the sucking of a limp dick with lots of thick saliva.
man i numbed my cock and gave my girl a glass of milk. that way she could give me a proper 'Slug Job'.