Heheh. The same day Stardust came out. Anyway more Axel/Demyx "headspace".
1. Axel often calls Demyx names that are easily insults, but used as "pet" names or sarcastic. Demyx is used to this and is far from an innocent, abused person as he also throws names at Axel too. It's "old married couple" stuff as opposed to actual verbal abuse. And yes, Demyx can tell the difference.
2. They frequently drive through the City That Never Was and in worlds where cars exist. Besides driving at nutjob speeds, they sing, they listen to the radio, they talk, fight, and yes, they do naughty things in the car. This did not change when Roxas came around.
3. Axel/Demyx dance together, but they seldom fight together.
4. Axel loves being "mean" to Demyx. IOW, Axel is often mischievous and frequently annoys Demyx and plays pranks on him. Demyx is also pretty annoying , but he is nowhere near the prankster.
5. They have schemed together and this is especially true right before and right after Chain of Memories. Yea, that's hard to believe given Demyx, but I've always believed that Demyx is little different from Axel. He's just nicer.