where does the ps in a letter go
Postscript A postscript may be a sentence, a paragraph, or occasionally many paragraphs added, often hastily and incidentally, after the signature of a letter or (sometimes) the main body of an essay or book. In a book or essay, a more carefully composed addition (e.g., for a second edition) is called an afterword. The word "postscript" has, poetically, been used to refer to any sort of addendum to some main work, even if it is not attached to a main work, as in Søren Kierkegaard's book titled Concluding Unscientific Postscript.
Mind your Ps and Qs Mind your Ps and Qs is an English language expression meaning "mind your manners", "mind your language", "be on your best behaviour" or similar.