it bends, it breaks

Safety in kink doesn't just mean having a safeword. It means having a plan to stay safe. Because if you're gaging on your doms cock it'll be kinda hard to yell "pineapple".

The easiest thing you can do it tap your partners side or arm when your mouth is busy.

You can snap or clap if your hands are free.

Have something on the heavier side in your hands that'll thud when you drop it that way even if your hands are bound behind you and you can't tap your partner then boom, immediate emergency button. Or alterinitively, you can have a clicker that'll get their attention.

You can kick your feet up and down, hell go get a rubber chicken and squeeze it. Or even a loud dog toy. Something auditory that you can make sure there's no miscommunication between you and your partner. But come up with a PLAN.