Not gonna work! The human body is biologically programmed to react to high levels of CO2. Which means your SI will kick in hard and fast, and it's gonna be so strong, you'll rip the plastic bag right off your head and sabotage yourself within seconds. This is basically a darker version of a kid holding his breath when his parents are emotionally abusing him. It's meant to scare the parents, but both the kid and the parents know it's gonna fail eventually.
What you want is to create low levels of O2 instead. (This was done by Dr. Stone (Sandra Bullock) in "Gravity", before she had a change of heart.) That's basically the night-night method, the CO method, or the N2 (molecular nitrogen) method. Those gases simply displace the oxygen keeping you alive, and your body is none the wiser, as the CO2 level is the same as usual. Soon, unconsciousness from hypoxia kicks in, and the ghost leaves your body.