I explained everything in the thread including how Kakashi was actually able to manifest it. It wasn't not an asspul. It's just that fans popularily were under the impression that EMS was required for the Perfect Susanoo when it was never said anywhere by anyone including Kishimoto, the manga or databook. Kakashi filled the requirements(double MS+Obito chakra). All what needed to be done was to pull the trigger and activate it in his stabilize form. Kakashi knowing the workings due to Sharingan simply showed his genius by activating and completely mastering the state in one go