An adjective that can be used to describe someone who pretends to love you one day but talks bad about you behind your back the next (or vice versa). Chances are, this type of person will make you heated.
I can't believe she complimented me like that to my face after what she said about me in the press yesterday. What a flip-flop, flippy, flip-floppin' lady!
More commonly referred to as Free Balling, Floppin' is going about your business without wearing underpants. Floppage is the degree to which you are Floppin' and this is decided by the Flop Factors, Temperature and Humidity.