When a nerd attempts to explain the inconsistencies in their favourite TV shows/films with supposedly 'common sense' conjecture based on non-canon material. Especially applicable to Science Fiction.
"Did you know that the Nova class science vessel was introduced to replace the Oberth class vessels in the 2360s?"
"Man, is that true?"
"Erm, don't really know. I think I made it up. Makes sense though. Wait, did I just have a fan wank?"