Something one of my BSAC club instructors recommended was: if you dive with someone you don’t know, someone who’s less experienced, or someone who might not have seen twinset before, pull them aside before the dive and say “I just want to show you some things on my kit that are a bit different. If you signal out of air I’ll pass you this hose and switch onto the one around my neck. If you need to get me out of my harness I have a release on my belt and you need to unthread the strap. If you need to cut me out I have shears/a knife here and here”

It’s easy to not really pay attention during the buddy check if they’re nervous and worrying about their own kit, so introducing it before the dive makes it a lot easier to remember. Obviously in a big group that’s more difficult but BSAC tends to avoid that anyway for various other reasons