An advanced and difficult to pull off version of a "standing 69."
1st: One participant must take said position with partner, but instead of having legs over shoulders, must wrap them around their partner's torso, while having their ass pretend to be breasts.
2nd: The two must then hold on while strapping the upside down partner with something (such as a corset) before putting on a special sized costume dress or garment to cover both participants (varying on size and additions for better disguise/costume), making the appearance of a large breasted woman or similar to such.
3rd: While upside down, the "ass breast" commits to giving a blow job to his/her partner, who may move about and possibly attempt to smuggle hidden partner to other nearby areas (distance adds to difficulty as the upside down position causes blood to rush to the head, and the sight of a woman's skirt lifting to show a head shaped "lump" can cause either alarm, or hilarity.)
"You think she's smuggling a 69 under there? She's huge!"