I still don’t know what that means , but I always read it as “Shit in My Hands”
Well that’s a different thing, as it’s not an abbreviation, but an acronym. Which is why that actually gave me pause after years of using “smth” online, because I always read “smh” as “something” instead of “shaking my head.”
It always bothered me because “shaking my head” isn’t even a figure of speech people say, so how the fuck can you use an acronym form of the expression.