Just open your mouth...
That's what I was gonna say.
Humming with your mouth open is singing, not humming.
no, if you do it through your teeth its humming.
No...you can hum with your teeth in any position. The only requirement is that your mouth has to be closed.
open your mouth as little as you possibly can, you can still hum.
You wouldn't have to open your mouth very wide to perform a blow job on my tiny little dick ;)
that was a terrible comeback (1) and it was to yourself (2)
i can hum with my nose plugged,i tried afterwards,and i didn't smile.