Please do not fill the flag queue with tag requests. Here is a much better and quicker alternative:
Include a note at the bottom of your question, or leave a comment after posting, specifying that a tag you wanted to add did not exist yet and it should be added by someone who has the privilege to do so. If it is deemed that the tag should be created, the person who creates the tag will also edit the message out of your post. If they don't agree, they can either leave the message for someone else to judge, or remove it if they know it should not exist.
It's likely a user with sufficient privileges will run across your question before a moderator responds to your flag. Let the community help you!
discussiontag, did you...? ;-)