smh stands for 'shaking my head', although it can mean 'stupid
minded humans' and 'so much hate'
either way you use it in a text/post/etc when your
disappointed, or if your friend did/said
something stupid (may be funny) you can say smh.
EXAMPLE 1
Friend 1 "bro
i accidentally pushed over
an old lady lmao"
Friend 2 "smh."
EXAMPLE 2
facebook post "a car crashes into a house and kills a baby"
person "omg thats so sad, smh."
EXAMPLE 3
Person "omg I walked out of the store forgetting to pay for my product
ahahah smh"
EXAMPLE 4
Mum "how do i turn the tv on?"
Daughter "lmao smh"