damn asking the real questions here
A responsible Dom would have a signal set up before hand with their Sub and would pay attention in case the sub used it. In rl subs have to be careful who they play with because being in the hands of someone who doesn't pay attention to safe words is dangerous and could possibly be deadly. Yaoi BDSM is far from what actual BDSM should be.
I have a question you know there is a safe word in the bdsm relationship but some of them also uses ballgags. So if their mouth is filled and they cant speak how are they gonna say the safe word? ┑( ̄Д  ̄)┍