It wasn't a joke. Since, they aren't giving each other oral sex, I wouldn't have thought to describe it as 69. There are other pictures after this one that show them both getting fucked while in this position, would you still describe it as 69?
Rainbow looks like she is tied up while Cammy looks like she is wondering what's going on and where she is... I would almost say she was drugged, but her eyes don't have that typical "out of focus" look, just confusion.
