If the rope is used in the mouth, it should be dedicated to that person only, or it should be a synthetic or cotton rope that can be thoroughly washed and sanitized.
More About Rope Gag
An effective rope gag can be achieved any time rope is run through the mouth. A rope gag is sometimes done in conjunction with a rope blindfold or as a way to use up the rope after completing another tie.
Specific rope gag ties also exist that mimic other typical gags such as a bit gag or ball gag by using patterns of rope work or knotwork.