Just explain whatever the problem with the post is. :) You don't need to go into detail, the moderators of all people know the rules, so we don't need to be given a paragraph. Say for example you see some really blatant spamming, you can just hit report and type "spam" in, and we'll deal with it. :)

As for yourself being reported... being reported does not guarantee you'll get in trouble. In fact, even if you did something wrong we'd still be quite gentle in pointing out your mistake to you. As long as you're doing your best to follow our rules, you really don't need to worry about it. It's not as if you'd be banned from the site for posting in the wrong forum! :)