The Double Decker sex position gets its name from the iconic double decker buses found in many parts of the world, particularly London, England. It is a form of rear entry sex that involves the penetrating partner laying on their back. The receiving partner then lays on top of the penetrating partner, back to chest, and supports themselves by propping up on their elbows and feet. The penetrating partner can then enter the receiving partner's vagina or anus.