Wear 10 pieces of masks together.
Confirm will suffocate to death?
It will be a fast and painless death?
Cannot.
You need someone to hold down a pillow on your face and put all his weight down and stop you struggling as well.
But that would be murder. Not suicide
You could also lie down on a sloped driveway wirh a car parked neutral put a block chuck at the wheel. Lie down in the path of the car then pull the string on the chuck block and let the car run over your head.
I think easiest just jump off a flat staircase landing higher than 15 floors.
Why do you want of commit suicide?
Get help
https://www.sos.org.sg/