it is early on in their relationship and Nico comes back from helping around camp, or training, or whatever, and witnesses Zeph hyperfixating (more like the result of it) for the first time? Like he just finds them curled up, asleep, in the middle of the floor, surrounding by the materials they were making their cosplay with, maybe they have paint on their hands, some smudged on their hoodie, pants, and somehow their face (their hyperfixation is shows and the characters from them specifically and they love making cosplays of them) and Nico just completely melts? Also Zeph remains asleep after Nico finds them for extra fluff :)