Also a cross over S&M'er one of my favorite things for this is the "drop" your given something to hold from a rubber band to a marble (marbles nice cause it makes noise) if you drop it, it counts the same as a safe word. Not to get into the whole safe word debate, but, a safe word is great, but it does nothing in the place of trust and an ever aware Dom, or in this case tickler. Someone under your power is your responsibility, take care of them safe word or no, Ive seen great Dom's who refuse to use a safeword and terrible Dom's who sware by them and visa versa. A safeword is a tool like any other and should not take the place of sound judgement.