The Box tie is a technique used in BDSM play which involves the restraint of a person's arms by binding them behind their back. The arms are bound with the palm of each hand on the forearm of the other hand. A rope goes round the hands and arms, and extra ties go round the upper arms to stop the bound person pulling their arms sideways. This is a relatively non-stringent method of bondage, and most people can endure it for prolonged periods provided the ropes are not so tight as to restrict blood circulation too much.
To immobilise the arms further, ropes or a strap are often placed round the upper arms and torso, pressing the arms against the back. Another technique is to tie a rope round the torso before the box tie, then tie another rope round the forearms and the torso rope. On a woman, these torso ropes may be associated with ropes for breast bondage.
A variant is to tie the wrists to the upper arms next to the elbow. This is more stringent, and can lead to discomfort and cramps.