Spreadeagle (position)
The spread eagle (also spelled spreadeagle or spread-eagle) is the position in which a person has their arms outstretched and legs apart, figuratively resembling an eagle with wings spread. It is a style that appears commonly in nature and geometry. In human style it is represented by the letter "X".
A spreadeagle is a common position in various fields. It is commonly used in dance routines, especially at the conclusion, in figure skating and at the beginning of sky diving.
Sex position
The spread eagle also refers to a sex position in which one partner lies on their back facing up (supine) or (less commonly) lying facing down (prone) with arms and legs spread wide apart. When the partner is lying face down, it is a variation of the doggy style position, and they are lying face up it is a variation of the missionary position. Another variation is for the receiving partner's legs to be closed, and the penetrating partner's to be wide apart. This variation is said to be better for stimulating the G-spot and the prostate gland and is sometimes called the peace sign position. The face up versions of the position are popular for oral sex play or erotic massage.
Another variation is to have a standing, vertical spread eagle.
These positions are classic ingredients in sexual roleplay.
BDSM
The spread eagle position is also employed as a bondage position in BDSM play, sometimes upside down. A standing or hanging position is usually achieved using equipment such as wooden crosses or spreader bars but can also be achieved with ropes or chains attached to different endpoints. As a humiliation technique it's popular for forcing the person to display their genitals and to provide unhindered access to the crotch, groin and sometimes anal region for sexual play and torture.