A drink of liquor brought with you on the side. Often smuggled into places, generally in a flask. Maybe at an expensive bar, a concert that doesn't allow liquor, to mix into a soda at a restaurant ETC. Usually not your main drink, but a supplemental one- however is generally acceptable as long as it is secret or not allowed.
"Shit man, these beers are $9. I couldn't afford to even get tipsy in this place. Good thing for my side liquor."
"Hey, you going to the dropkick Murphy's concert? They only have beer so I'll bring some side liquor"
"When I'm playing beer pong I always like to have a side liquor while I play"
Super=Of a higher nature or kind.
Imposed=To apply or make prevail by or as if by authority
This term was first recorded in The TalkingGoatSkit By Adam Sandler.
They Super Imposed me what the hell was I suposed to do?