With the bag there could be convulsions and in an unconscious state the suicidal person could take it off.
In order to hold the gas inside the bag, you're supposed to secure the bag tightly around the neck with something like electrical insulation tape. After that, it would be somewhat difficult to get rid of the bag even while you're conscious, not to mention the unconscious state. If you can do sophisticated well-coordinated moves unconsciously, then your amazing autopilot probably can make you running out of the room as well.
Perhaps, you could use handcuffs to protect yourself from moves like that, but the problem appears to be purely artificial to me.
What equipment is needed to produce CO as you say?
A flask or a glass vial (200 - 500 ml), a funnel, protective gloves, a roll of electrical tape, scissors, and a durable plastic bag (20 - 40 liters) would be handy.
Are gloves and protection needed?
It's possible to work without gloves, but you have to be very careful then. Concentrated sulfuric acid doesn't cause burning sensations on a contact with the skin until a substantial damage is taken. If you wash H2SO4 from the skin immediately, it won't do any serious harm (well, unless the acid is hot).
Whether you need to build a filter for capturing the fumes of formic acid is unclear. I've never dealt with this reaction and can't tell how much acidic fumes it can produce. All I know is that theoretically they could be produced.
A filter may consist of gauze soaked with a solution of NaOH or Na2CO3 in water and placed inside a hose. NaOH also makes protective gloves worth using.
How would you proceed if you had to explain it to a novice?
Probably no one reading this thread will follow these instructions anyway, so writing them here in detail is not worth the effort.
The idea is to attach an alkaline filter to an empty plastic bag, then mix two chemicals in a vessel (the reaction should happen at room temperature without additional stirring), attach the filter to the vessel, so that produced gas would go through the filter into the bag. If the reaction almost ends (becomes very slow) before a sufficient amount of gas is accumulated in the bag, the filter is detached from the vessel, then the entrance to the filter is temporarily closed, and the procedure is repeated till the bag is inflated enough.
When 5 - 10 L of CO is accumulated inside the bag, the bag is detached from the filter, quickly placed over the head and sealed around the neck with electrical tape while holding breath. When sealing is done, you resume breathing and have happy sleep.
This is like trying to commit suicide by Tylenol pills
Seriously? Can Tylenol pills cause nearly guaranteed unconsciousness in a few seconds and death in a few minutes after consuming?