1. The repeated and often rhythmic sound created during elderly sex.
2. The flapping of loose, dry skin against loose, old skin.
I was walking down the hall past Verna's room and could have sworn I heard the sound of Seymore flacking her!
An older woman getting with a youger man/teenage boy around 10 or more years younger than her and makeing him her "ToyBoy". Commonly frowned upon especially by teenage girls who would rather the guy be with someone his own age and not with a cougar.
Made famous by the UK Xtra factor host Caroline Flack (32) getting close and personal with Harry Styles(17) member of the British/Irish boyband One Direction.
Girl 1: "OMG! Did you here about that senior boy haveing an affair with that 33yr old?!
Girl 2: "Are you serious?! No! Eww thats soo bad! And to think I had a massive crush on him before."
Girl 1:"IKR! I wish that stupid cougar would Eff off, stop Flacking and get with someone her own age! ugh."
To "kill someone softly" as in the Roberta Flack song.
She has been so lazy and flacking lately.
Man, Ryan Knowltan is always flacking when he gets home.