An MD Slug is a person who takes way too much MDMA and ends up on the floor or in bed the whole next day, in other words an MD Slug will beg other people for the drug and slurp it up out of their hands when they get the chance.
"He took a whole 2 grams of MD last night at that rave, and now he's tucked up in bed like the MD Slug he is"
by Six Foot Duck September 22, 2016