Responses

Depending on the level of the BDSM relationship, there might not be a safe word. A really, really good dom is experienced enough to be able to read the bottom's body language and know when they need to stop or slow down, or even to push them further. Safe words are used a lot more when it is two people having a scene, who are not necessarily in a relationship, just having fun together.
Okay I'm sorry but this is not good BDSM because they always have a safe word and if they consented to it then they have to stop if it's said, and this just looks like it hurts and he's putting up with it because he loves him