Its important to know your partner, read the body, and listen to the voice, talk before a scene, learn turn on/off triggers. Discover the limit and when to push it. As a top it's all on you, every bit of it. As a sub you need to communicate clearly, and dont compromise to make the Dom happy. When I top I rarely have a safe word spoken to me, because i have a pre play talk. I rarely need to tie a woman down because they want to be there, because it's a good scene, and a good scene is good for everyone!