Traditionally, a common fetish has been the worship of a foot, and this is common in BDSM today. Traditionally, a slave would kiss, lick, smell, and/or grovel before their master's foot. This has a very strong link with the shoe fetish.
The feet have many nerves, especially along the soles, and striking the soles induces a sharp, stinging pain. As such, feet have commonly been used for corporal punishment, using techniques known as bastinado or falaka. Traditional spanking implements can be used, although smaller tools, such as rulers, are favored, due to their relative size to the sole of the foot. Feet are commonly placed in bondage, as it is a relatively simple process to bind the ankles of a subject using nearly any material. Furthermore, certain restraints, such as stocks and shackles, are designed to restrain the feet.
Feet are one of the most commonly ticklish locations on the human body. For fun (or sometimes torture), the feet of a subject are restrained and tickled, usually with the subject being unable to prevent the tickler from stopping.