I'm quite surprised that I couldn't find a post about this matter already. It seems like something that people would have many different opinions about. Either way, I'm sure there are many methods out there that people like when teaching a complete beginner about how to form a trumpet embouchure, besides the old standby of "Mmmm, pooo" or "Mmmm, buzz" into the mpc. My cooperating teacher in student teaching had the students make a buzzing sound without the mouthpiece first, because it's almost impossible to do so with loose corners or puffy cheeks/lips. Once the student was buzzing with only their lips, he would have them place the mouthpiece on the embouchure in the middle of the buzz, and then eventually rearticulate to teach them how to start the buzz with the mouthpiece on. Of course this was only used in the first few weeks in order to get the concept firm in the students mind (any longer and the students would develop stiff embouchures as well as stiff sounds). I want to hear other ideas on this subject and why they are beneficial.