How to sit with exit bag on

[Wiltshire]

Hello, I read the PPH and the threads where I think this was mentioned once but I couldn't seen an answer. If you'll be reclining slightly in an armchair-but the back of the armchair is such that some of the back your head rests on it - Is this really an issue. I tried the bag on my head and sat in the armchair and there is still plenty of space around the mouth In the bag.If you can't rest your head lightly on the back of a chair, surely you head would drop forward or to the side. I welcome thoughts. Also, and I know this is been raised before but the PPH says the bag should be loose around the neck. I've seen people say it should be a Snug fit and that you can get your fingers underneath it. Is that meaning there is a gap already there that is finger width OR where you can easily push your fingers under the elastic but it's otherwise snug to the neck (but then surely that's not a loose fit). Do you know what I mean so a gap all around the neck about finger width where you might slip your fingers under to allow the co2 to go out easily. surely if there are no gaps at all, the CO2 wouldn't be able to escape. Can it really push through the snug elastic? If there is a gap around the neck (loose fit) doesnt the weight of the helium pushing down from the top of the bag make sure that no oxygen gets in through that gap and that the CO2 can get out? I have read the PPH handbook. This really is the further clarity on what is a loose fit. thank you! Very much.