I always put it to my email. I save it in my drafts and applying some secret code to the phrase just like adding some letters on it so that if ever my email was hack. They will not use it since it was wrong and it is very hard to determine what is the character that it makes wrong. Trust me, No one can use it but just remember what and where do you put the additional character.
People doing this are insane. You should consider all email providers as NSAware, the hosts themselves probably can ready any email they want. If I had to choose one I would at least use something decent like Protonmail which supposedly it's all encrypted and they can't access your mail. Also log in through a Linux live DVD to guarantee your OS host isn't compromised, and do not store the entire seed. I haven't done the math but I would at least try to remember the last 4 words, or two first and two last, and that is already a compromise.