Sit the Fuck Down
Used when someone just says something obnoxious and you need to put them in their place
Keenan: Aww man, my parents aren't getting me a Mustang for my 16th birthday. This is so unfair.
Damien: Dude, STFD. stop being a douche.
Sit The F*ck Down, a taunt used in Weight Watchers Fitbit or other fitness device challenges. The person using this expression would prefer the other challenger(s) to stop increasing their step count or calories burn.
I've just been overtaken! You need to STFD because I need to win!
Shut the front door ( replacement for stfu- shut the fuck up or shut your mouth)
stfd, don't want him to hear us!
Shut-The-Fuck-Down.
Changed version of STFU which means Shut The Fuck Up.
Joe: Your stupid.
Jim: STFU
Joe: STFD!
Knobjockey: 'Wow, yesterday me an my mum went to the Royal Show. I got the Inspector Gadget showbag, the Neverending Story showbag, the Pound Puppies showbag, the...'
*Slap*
Greg 'STFD'