make the beast with two backs

To engage in sexual intercourse with another person, referring to the exposure of each partner's back when embraced in the missionary or standing position. I have my suspicions that, in secret, they are making the beast with two backs.

Common Names:

Name	Pronounced	Usage
Torsti	TOR-stee	Finnish
Beau	BO	English
Didier	deed-YE	French
Constantine	KAHN-stən-teen (English)	History
Blanch	[bla:ntʃ]
DonÁT	-	Hungarian