https://pheromonetalk.com/t/question-about-layering/17065 https://pheromonetalk.com/t/layering-or-mixing/30814 https://pheromonetalk.com/t/layering-or-separate/34016 https://pheromonetalk.com/t/question-about-applying-layering/38229
There are countless threads on this topic. Search is your friend, man.