When a guy with a huge dick pulls away while his girl is on her knees blowing him and he starts swinging his big prized cock across her head, just like a prehistoric caveman would whack his woman on her head with his caveman club.
I Fred Flintstoned my bitch on her head last night...yabba dabba doo.

After I pulled a Fred Flintstone on my chick, she saw stars all night long.

Lucky my girl got no bruises on her head after I Fred Flintstoned her or I be arrested for domestic violence. shit.
by king_muscat April 16, 2010
The act of slamming ones feet through the floor of the car, and onto the pavement, to stop the car.
Dude i gotta pee, if you don't pull over i'll fred flintstone this bitch.
by b-radical the magical January 8, 2009
To date two or more girls simultaneously. This refers to the 1/19/62 Flintstones episode #44 "The Entertainer" when Fred has to manage two dates at the same club when Wilma unexpectedly shows up. Of course, he had the help of Barney to distract them as he switches between girls (this will not always be your case). Even though he was ultimately unsuccessful, the expression remains.
Man, I forgot about Caroline and invited Audrey out too... I can't cancel now, I'll have to pull a Fred Flintstone.
by FredFlintstone September 27, 2008
a very short "stubble" beard around 8-12 hours old.

see 5:00 shadow
I have to shave twice a day; otherwise I'll have a Fred Flintstone by 9PM.
by BJT9000 January 9, 2003
A man pitifully out of touch with modern life, especially with how to treat his significant other.
Fat Lazy Piece of Crap-Get me a beer and and make me a sandwich!
Chick who Goes with Him-Go get them yourself, you fat tub of goo! I'm busy!
by Shawn B. April 30, 2003
Going down on a woman while she is on her period; coming up Fred Flintstone faced.
His face was two-toned like Fred Flintstone after that unfortunate encounter.
by Gison April 13, 2010