The term slug is utilized to refer to someone as a “dumbass.” Use slug is an infinite so it can be used for the past, present or future.
If you say, someone’s “sluggin,” that means they’re currently being a dumbass. Sluggin is for present tense only.
Raven do you not know how to swim? You’re so slug!
Did y’all see how she tripped over nothing? Caught sluggin’.