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1.
Established Winter of '04. Used to describe the act of flopping around on the sofa all Sunday long. One resembles a Flounder out of water flopping as it gasps for air, in its case, water.
We floundered all day and loved it.
by Luis March 04, 2005
 
2.
The act of taking ones hand and placing it in someone else underarm and shaking it as if it was a flounder out of water.
I am floundering my friend.
by Scott17 March 21, 2008