Carnaval Dildo?!

Every single person who has watched the big Rio de Janeiro Carnaval parade has wondered about how the tapa-sexos (Cache-sexo in English) stay on.

Know what a tapa-sexo is? It’s this:
Yeah, not much to that bad boy. And see those muscular legs? This woman is about to samba for 90 minutes (or more) and make that little piece of tapa-sexo hold on for dear life to whatever landing strip fits under a costume like that.
So how do they stay on? This is the question of the day! Mr. Rant said he saw some forward that explained it all. We found the picture:
Yes, this is exactly what you think. Apparently someone is trying to convince the world that the tapa-sexos have a thumb that sticks up the vagina and holds that bad boy on. This only shows how little ¬†men knows about the vagina. I’m sorry guys, not even Wonder Woman’s Vag would be able to clench onto this little guy for an hour and a half of samba. Hell, I doubt she’s make on a 2 block walk to the grocery store.
Seeing that the dildo inspired tapa-sexo only exists in this shell version, I’m thinking it’s one man’s dream to see an image of his thumb somewhere where no one will allow it.
I find it much easier to believe that they are glued on, only to be painfully ripped off later. Kind of like this:
Now I realize that there is a version that is made out of metal that is made to size and squeezed on for dear life:
But if you would please refer to the first photo of this post and look at the butt. There is nothing back there. That would have to be one skinny and uncomfortable metal stick suffocating between those cheeks.
So what is it? Thumb, glue, suffocating, or none of the above?