I think it's important to have multiple levels of feedback as a dom, which is why I prefer to use the green, yellow, red system rather than a simple safeword. My pet and I, however, also add another word 'blue', which rather than being a simple 'stop' like red, means 'i need to stop temporarily, but would like to keep going when whatever issue that is troubling me has been sorted out', whether that's a cramp or whatever it may be.

It is important for responsible doms to constantly reinforce upon their sub that there is no shame, stigma or disappointment attached to using a safeword- rather the sub should be proud that they can honestly and quickly provide their dom with the information they need.