SMH is one of the many acronyms used on the net, like LOL, ROFL or RTFM, but unlike the others it can have more than one meaning
SMH: who has not encountered it in messages or on the net, perhaps in some forum or among the posts of their friends on social networks, raise your hand. What is meant by this particular acronym, however, is not known to all, indeed: yet it represents an action so common that we all have done at least once in our lives.
The meaning of SMH is simple: "shake my head", which in Italian can be translated as "shake my head" or, in a broader sense, "I disapprove". The meaning of SMH follows in an approximate way that of facepalm, that is to cover the face with one or two hands as a demonstration of disbelief and blame. Like other abbreviations has now taken hold in the common language, such as LOL ("laughing out loud"), ROFL ("roll (ing) on the floor laughing", ie "rolling on the floor laughing" and the now historic RTFM ("read the f* manual", "read the damn manual" to say it in calmer terms than the original). It is therefore not unusual to read or even reply with a short series of characters that actually encapsulates a more articulate and targeted response.
SMH: when and how to use it in messages
When you encounter abbreviations of this type, it may not be easy to use it correctly. That's why it's always best to familiarize yourself with network terminology before using it in the field.
As mentioned above, SMH basically sums up the action of shaking your head. The reasons for doing so can be many: from disappointment to shock, to showing disgust or disbelief at another person's statement.
Of course, deviating slightly from the original meaning, it can also be used in front of a joke, just like when in real life you laugh while shaking your head to amplify the effect of the laughter even more. Practically every action that normally implies this kind of head movement can be summarized with the acronym SMH.
SMH: where to put it in the sentence
Like other network abbreviations, SMH can be used anywhere in the sentence, at the beginning as well as at the end to reinforce the message. And if words are really lacking, these three letters can be used as a single expression, representing the image of an intense and sudden reaction, perhaps associated with the even more famous facepalm.