First of all, a little bit of context.
I have been playing the trumpet for one year and a half already. I am undergoing my second change of embochure, so I really want to do things right not to start again one more time.
I have read that buzzing the lips is very important because it helps to develop the muscles that we should use while playing the trumpet. The good thing about buzzing the lips is that you cannot "cheat" and produce the vibration via pressing your lips against the mouthpiece.
I have seen a lot of YouTube videos in which people explain how to buzz. It seems that they just close their mouths and producing the buzz is authomatic. Nevertheless I am really struggling to get it.
I am able to play long tones (from the first G flat under the staff to high E) with a decent sound. Nevertheless, I am completely unable to buzz my lips.
My questions are: is this normal? Does this mean that I am using a wrong technique to play (i.e. "cheating" like explain above)? Is it just a matter of training? What should I do in order to learn how to buzz?
Any help would be appreciated.
Edit: Actually, I am able to make some kind of buzz. In order to do it I have to hide almost all the red part of my lips and to separate the upper lip from the teeth (I look like a duck when I do this). I am not sure if this way of buzzing helps to improve my trumpet playing because I do not have to flatten the chin to get higher notes as suggested in the tutorials that I have watched.