"To turn off automatic switching, go to Settings > Bluetooth, tap the Actions Available button next to the name of your AirPods, tap Connect to This iPhone, then tap When Last Connected to This iPhone."
Heard about it but I would love to use switching if it worked :-( Btw the “AirPods connected” notification visible on the iPad while the built-in speakers are screaming at everyone around me is phenomenal.
You can turn it off by doing this:
"To turn off automatic switching, go to Settings > Bluetooth, tap the Actions Available button next to the name of your AirPods, tap Connect to This iPhone, then tap When Last Connected to This iPhone."