The cross-shaped piece of equipment that is often used for bondage play is called a "St. Andrew's Cross". It consists of two perpendicular wooden or metal beams, with straps or cuffs attached to each end. The person being restrained stands with their arms and legs spread apart, secured to the beams by the straps or cuffs. The St. Andrew's Cross is a popular piece of equipment in BDSM play, as it can provide a sense of vulnerability and exposure for the restrained partner, and can be used in a variety of ways for both sensory and impact play. However, it's important to use the St. Andrew's Cross safely and responsibly, and to ensure that both partners are comfortable and consenting before incorporating it into your play.