The act of shoving your head up someones rectum whilst having sex.
Dian- Yea chad he just flipped me over and just started flintstoning me.
Susan- Oh my god are you okay that must've hurt you're poor ass.
Dian- You haven't lived till hes done that to you.
Being in the middle of a task at work and just dropping it and leaving the minute your shift ends.
(In the first 10 seconds of the Flintstones intro, Fred is busy lifting a rock out of the quarry, but as soon as the whistle blows he's out of the quarry and into the car)
"Never give him a task that takes more than 15 minutes at 4:45, because he'll be flintstoning on out of here at 5:00."