a swig is between a sip and a gulp when you take some of your celestialbesties family friend's drink!
I took a swig from my fiance's fountain drink she got at the store after she went to the ATM to get her money from her job she is tasked with and on assignment to complete from heaven with the divine blueprint of the Heavenly FaTHer God of Gods and goddesses YHVH ELohim New Jerusalem 12 gemstoned City of God with 12 pearly gates that never close and that there is no night there because it is always thriving and booming electric super charging atmospheric energy kraking fissures in the world! BAM!
A swig is a sip or swallow of a drink. Dig, in this case, is the drink (usually Gatorade). You ask for a "swig of that dig" when you want to have a bit of your friend's drink. An alarmingly common request among teenagers (at my school).
Bob: Yo, lemme get a swig of that dig!
Tom: No way man. Not with that on your mouth.
Bob: Come on I'll do a waterfall.
Tom: No.
Bob: ...
Tom: ...
Bob: That's cold, dude.
A liquid that, when ingested by a human being, will inject copious amounts of melanin into their skin.
This will transform them into a nigger. If they are already a nigger, they will become even more black.
Repeated consumption will result in the skin getting blacker, until a gallon is ingested, at which point you will turn into a black hole.
Person 1: Hey dude, I took a swig of Nig last night!
Person 2: Nigga, you're so black now it looks like you took 5 swigs of Nig!