"I have a really... Enthusiastically loud and slightly embarrassing friend/kouhai... Any advice? (If you don't know who I'm talking about *cough cough* @RaeOtakuKat who claims to be your fiancé I apologize in her place."
Well, I've dealt with annoying kouhai, but yours seems to be a close friend. Honestly I think you should be up front with her but if you're uncomfortable with that, just fluster them when they're being loud and annoying. Usually it'll shut them up. Just talk about a crush or an embarrassing time in their life and they will be to embarrassed to say anything or will squeak like a mouse and deny everything, which is amusing rather than funny.
Cherish your friend, though. They may not be with you for many years and you may drift apart. Enjoy the time you have with them now. They may be annoying but when you really need to deal with them the most, remember to make the most of your time.
