SMK means Slapping my knee.
Something is so funny that you are slapping your knee
Did you hear the joke that Josh made? I was totally SMK.
The history of smk:
On August 1, 2018 at 8:20 pm I misspelled SMH and SMK became a thing It originally meant Shaking My Knee bUt has been updated to mean Showering My Knee. SMK bro. SMK. It is extremely rude to SMK at a fellow dude tho so no do that.