I would like to ask a specific question about using em dash dialogue in (mostly) fiction writing . I would like to ask if there are any specific rules about how it should be composed, the arrangement of the character dialogue and the speech tags, and what type of description is not appropriate to go inside the dash-dialogue passage. I have already asked it to the Writers.SE group, but I thought this group could also provide a useful answer. Is this question off-topic? If it would help, I could edit this query and insert my original question from Writers.SE.
If the question is about writing style, Writers is the right site to ask your question.
As you already asked your question on a site, you should not cross-post the question, if you don't adapt it to the site where you ask it. As the question is about writing style, I doubt there is a way to adapt it for EL&U. If you make it a generic question about using em-dashes, it is probable that a similar question has been already asked on EL&U.