The trainer places it on the fighter's head before the ritual and takes it off, with a short blessing, before the bell. In between, the mongkhon sits on the head through the whole wai khru ram muay, and the fighter does not touch it. It is not theirs. It belongs to the camp or the teacher, and that is the point.
Traditionally a mongkhon was blessed by a monk or made from cloth that meant something to the teacher. Many camps now use a standard braided cord, but the etiquette has not moved: on before the ritual, off before the first round, and never worn outside that moment.
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