A woman having multiple partners simultaneously allowing them to exchange positions or rotate in. Commonly in a counter clockwise motion. Each man has an opportunity to fuck the woman in each of her holes.The exchange can be as quick as a few pumps each or as long as a few minutes at each station. A mery-go-round can be accomplished with as few as 3 men to a gang bang.
A woman is doing a double penetration (woman on top). She is sucking off a 3rd man. The man fucking her in the ass vacates her asshole. He goes to the end of the line. The man receiving the blow job goes to her asshole while a new man rotates into receive a blow job. There are many variations to the merry-go-round.