Again with them, any fic that takes place when they were younger calls them Doug and Guy.
Additionally, Tohru's friends have nicknames for each other, and Hanajima gives one to Akitoto show that they're starting to become friends.
She's upset at first but is talked into accepting it's OK for him to do this.
Scott actually accepts this nickname whole-heartedly, and even refers to himself as such when talking with her sometimes, especially whenever they're being lovey-dovey.
Twelve year old Azula marched through the castle with a frown on her face.
Compare Insult of Endearment.
It could be removable or it could be a part of his head.
I liked him with Suki better so I thought 'why don't I just put her with Naruto' and went with it.