Is it allowed to ask questions about argot or even vulgar terms? I would like to point out it is difficult for a foreigner to find reference on the subjects. Moreover argot is very common in informal situations, making vital some knowledge of it in everyday life.
I have no issue with this. As far as I know, neither EL&U nor GL&U have any. So I guess it's OK to ask questions about anything that is French.
Given how widespread the usage of "argot" is in French, it would be shocking if this was not allowed. Moreover, since we want to move (rightfully) away for simple translation questions, questions about argot usage, in which situation/environment it can be used/not used, the origins of the words, etc... appear to me as very appealing for this site as it is not something that is easily available elsewhere.