@freemo I needed to be vague on purpose. I wanted to check without exposing the name.
@freemo the video reminded me of something I used to experiment with in the local swimming pool.
If you exhale a sufficient amount of air you can actually sit comfortably on the bottom of the pool without floating upwards.
It's not a joke. I don't refer to drowning. It's just that the oxygen is in the blood, etc., not in extraneous reservoirs, making me heavy enough to sink.
I think my trick uses the same basis as what the video explained.
@freemo that one