SMH

"Steady My Head"
To be said after something ridiculous or embarassing (to someone else) happens.
Essentially telling someone that you need to have your head "steadied", in reference to the head shaking in dissaproval or moving with laughter, because what has just occured it so outrageously funny or embarassing to the other person.
This can be pronounced verbally as "smhhh" or "smuh".

Dude: You look mad nice girl.
Chick: Can't say the same bout you.
Other Dude: SMH (smhhh)!

7👍 153👎