A stack is a percussion device, mostly disciplinary, is a thin flexible rod, most often braided in leather, with a handle and a spank at the end. Like many other devices, the stack was created primarily for a utilitarian purpose: controlling a horse. In modern stacks, the inner rod is most often made of fiberglass, previously it was used for this purpose specially treated flexible rod, There are also stacks with a metal rod, but they are generally considered too rigid for BDSM. Instead of the traditional leather braiding, plastic covering is also sometimes used. Classification of stacks by length and type of spanking: - show jumping, or English (english crop), has a medium length (about 75 cm) with a narrow spanking - dressage (ridding crop) - long (about 100-120 cm), with a halyard at the end instead of a spanking - racing (bat) - short with a wide and stiff spanking, and the spanking can be single or double - doggin` bat - also short, with a wide stiff spanking of greater length, These variants of stacks are not exhausted: for example, some may have one or more tails instead of a spanking. There are also sets specially designed for BDSM, with interchangeable spanks: single, double, shaped, halyards, etc. The rod can also be interchangeable. Stack is relatively rarely used for spanking, except as a punishment. It is used mainly for the same purpose for which it was originally created: control. In the case of BDSM, for controlling the bottom, its area of application is disciplinary play, and of course dog-play and pony-play. It is best to search for videos on stack work by its English name (Crop).