Gag does not remove posts on the request of a user. The only reason a post will get removed will be if it breaks the terms and conditions here. Also moderators can only hide something they can not actually remove it, only admins can remove things.
You can't, no posts are removed per request, only posts that break the rules will be taken down. If you think the post reveals too much sensitive/personal information, you can contact the Admins to ask them to remove it. http://www.girlsaskguys.com/contact
You can't get it removed however if you aren't already anonymous I would go change it and then I would disvow it so you basically won't have anything to do with it anymore by clicking on the the image that looks like a broken link that appears under your question before you click on it.