A term of farewell, whether it be for the day or state of mind, referring to the switching from side A to Side B on a vinyl record player (also known as the flipside).
"I'm outta here. See you muthafuckas on the flipside."

"Here's a ten strip of acid, I'll see you on the flipside."
by Wasps In My Brain March 1, 2012
Telling your friends you'll see them later , or whenever you catch them around.
by Kg August 29, 2015
From the Saturday Morning program entitled Kidd Video.

Flipside--the cartoon world that the band was sucked into from the "real" world.

Wherever you will see someone in the future in a completely opposite setting.
Just before droppin some "E"----"See you on the flipside."
by The 801 Dick Bandit May 29, 2009