"breath_play" and "choking" both implicate "asphyxiation".
They're often used to tag images that either aren't extreme enough cases to cause oxygen deprivation, or don't yet depict symptoms it. There are no distinctions between lightly constricting the neck or impeding breathing, and strangulation or smothering. So blacklisting asphyxiation would block posts like:
But also block posts like:
People are also neglecting to use the "forced" or "unwilling" tag when there's clear distress or injury.