When one sends another man to a girl's house for some birthday sex and a viewing of Flintstones in Viva Rock Vegas, and when the guy gets there, the girl is sleeping and doesn't know why he's there.
Pat: Hey Alec, did you get together with Sydney last night for some birthday sex?
Alec: Nah man, I got the Flintstones Treatment...
The act of penetrating from the rear, her legs being wrapped around your waist, she is holding herself off the ground with her hands, all while simultaneously moving forward with you in a very "cave man," Fred Flinstone Mobil type fashion; all while shouting "Yaaba Daaba Doo!"
I knew the very moment I met you, that we were destined to do the "Fred Flinstone" with each other.
Noun:
A finishing move performed by a male. When he cums, he yells at the top of his lungs "yaba daba doooooo" and cums on his partner. The louder the better.
*guy pumps very hard*
"I'm about to... yaba daba dooooooo!!!!"