Definition - What does Spreadeagle mean?
Spreadeagle, in general, refers to a position where the arms and leg are spread open, like a bird with wings spread out. It looks like an X and can be executed either standing up or lying down. Spreadeagle is often used in reference to sex. The person can be spreadeagle while facing up or down. The position can increases feelings of vulnerability.
Kinkly explains Spreadeagle
As a sex position, being spreadeagle, face up or down, is a good alternative to the missionary position and the doggy-style position. It is a good way to enhance G-spot and prostrate gland stimulation. The BDSM community varies it up a bit by using physical restraints, such as hand cuffs and ankle cuffs, and spreader bars. This increases the feelings of vulnerability.