Safewords are a whole other topic but I can say in around 40 years of doing sessions I’ve rarely discussed them or been given one. it would seem the goal or desire would be not to safeword but everyone plays differently. I can say that the Dommes I have played with have always been able to read me very well and I can remember a time or two where I just was not in a good head space and said something to the effect and the scene stopped. I still regret those times too even after many years.