"Hantai" is a Japanese term that refers to a particular type of fetish or sexual preference. In English, it can be translated to something like "restriction play." This generally involves the use of bindings or restraints on the body, often as part of BDSM or kinky sexual activities. The person engaging in this practice might enjoy being bound and controlled, or they may enjoy having control over someone else's movements by binding them. It can be a form of power exchange, sensory deprivation, or simply a means to heighten excitement and pleasure during sex.