Living Submersible Mount [three-actions] Feat 5

You can reshape your body to provide a safe means of undersea travel for trusted allies. When another PC rides you as a mount while you're using the Living Submersible ability, your expert coordination allows them to take three actions at the start of their turn rather than the two they normally could take while riding another PC. You still gain only two actions at the start of your turn, instead of three, as you spend one action keeping your rider safely contained within a protective foam layer on your back.