The X-cross, St. Andrew's Cross, Crux decussata, X-frame or saltire cross is a common piece of equipment in BDSM dungeons. It typically provides restraining points for ankles, wrists, and waist. When secured to a saltire, the subject is restrained in a spreadeagle position.
The submissive may be attached to the cross with either the back or front facing the cross. Being restrained facing the cross is the position often used for whipping. Being attached with one's back to the cross is usually more of a sexual bondage position or used for sexual teasing.
Saint Andrew's Cross