My lips touch on “one.” You can make the sound to start the “o” with your mouth shut. Also- “w” and many other sounds when enunciated have your lips touch.
Perhaps. But that is not what they said. Regardless though- you can easily do “one” with your lips fully closed at the start of the “O” by using your throat and nose.
If you make a sort of closed mouth pucker like to whistle but lips together, you can begin the “O” without an “M”. It’s an exaggerated version of the movement your mouth tends to naturally make when making the sound, which can be missed when some quickly. The common cousin to this is “Hwon” etc. where a person has their lips apart and begins the sound before they begin separating their lips for the “W” sound.
Your lips touch at the start of one because they’re already closed before you started counting
You’re really saying “mwon”