A nose hook is the act of pulling up the nostrils, or a tool used for doing so. It is performed as a type of nose torture. While it is used in heavy SM play, it is also used in a wide range of scenes such as broadcast variety shows.
As for the tool named the nose hook, by hooking it on both nostrils and pulling it upward (in many cases, a belt or chain passes over the head and is connected to a collar to maintain tension), the nostrils are stretched vertically. It is something that gives shame to the wearer, but there are types that pull sideways, and they are often used in combination with normal ones.
Since it is a tool or action used for face torture, other tools that incite shame, such as ball gags, mouth spreaders, etc. are often used in combination with nose hooks.
The special move of Gintama, a character in Shinpachi Shimura, is the nose hook destroyer, which is a technique in which the opponent is hit with a nose hook with a finger and then thrown on his back. By the way, the first victim was Gin .