The wikipedia definition of safe word is as follows:
A safeword is a codeword or series of codewords that are sometimes used in BDSM for a submissive (or "bottom") to unambiguously communicate their physical or emotional state to a dominant (or "top"), typically when approaching, or crossing, a physical, emotional, or moral boundary. Some safewords are used to stop the scene outright, while others can communicate a willingness to continue, but at a reduced level of intensity. Safewords are agreed upon before playing a scene by all participants.
Please don't think you are "above" having a safe word. It is for your own protection, as well as that of your sub. It is not a sign of weakness to have one, nor it is a sign of trust to not have one believing that you know each other's limits implicitly. It's also a great device to give security to many of the new Dommes who come to this website seeking confidence or who worry about hurting their partner. Having a safe word and practicing it often, will give you a lot of the confidence you seek. You'll feel secure knowing that your sub wishes to continue and that he doesn't really mean it when he's begging you to stop like a baby.
With a safe word in place, during your scene your sub can scream "no", "stop", "you're hurting me" all he likes as part of the scene, without really meaning it or without seriously meaning for you to stop. So, the safe word needs to be a word that neither of you would ordinarily say during sex or during a domination scene.
Make the Rules
First, decide together what your safe word means. Does it mean that the scene stops entirely? Or does it mean that just the current activity stops? Establish what it means, and then practice the word a few times so that you don't forget it!
Next, at the start of every session, remind your sub of the safety word, or better --- ask him to repeat it for you to insure he knows it. "What's your safe word?"
Choose Your Safe Word
Now, what to choose as a safe word. Here are a few ideas that have been suggested:
"Uncle" (one of my favorites)
"Red Light" (another excellent choice)
"Safe Word" (During the throws of passion during an intense scene, a sub may not remember the safe word. In this situation, you may actually want to use the words "Safe Word" as your safe word.)
The possibilities are endless.
Using Colors as Safe Words
Green. Yellow. Red. One way to use safe words in order to seek feedback without interrupting the scene is for the Dominant to ask the submissive, "What's your color?" The sub can reply "Yellow" meaning that he's nearing his limit, or "Green" if he wants to indicate that he's fine, or that he wouldn't mind if you pushed harder. And of course, he is to indicate "Red" if he's over the limit, and wants to stop the current activity.
One of the subs who visits this website shared that he and his Domme use two words. Without prompting from his Domme, he will say the first word, "Yellow Light" to indicate that he's nearing his limit, but doesn't want to stop, and the other "Red Light" means that the line has been crossed and it's time to stop immediately. (He reported that he has never had to use it so far).
Non-verbal Safe Words
What if your sub is gagged? In some circumstances, the safe word may not be an actual word, especially if he is unable to speak. In a situation like this, it's more critical than ever to have some communication signal worked out. The signal might be dropping a bell, or a ball, snapping his fingers. He could open and close his fingers from open hand to a fist repeatedly. He could make three rhythmic grunts as a signal. It's also common for a Domme to put a finger in her sub's hand to check in with him - In this case, the sub would squeeze her finger to indicate "OK".
Be Safe, Sane, and Stay Consensual
Above all, honor the safe word. If you even tease or joke that you might ignore it, you will lose the trust of your sub. Trust is something you both need. He needs to trust that you will honor his limits, and you need to trust that he will be honest and communicate effectively.
And please check out the other safety tips that I offer on this website as well. Enjoy your sessions, my dears.
PS. Sometimes new Dommes get stuck looking for the right safe word. Feel free to share your safe word ideas below.