@Dutchy,
LIBRARIANS
Lovers in black rubber are responsibly INDULGING a necessary sexuality.
By that is meant that no offspring will result. Which is good for global warming. I once calculated the oil consumption of an American baby with 80 years to live. It was shocking.
It is a field well catered for by manufacturers and is popular with those who have become jaded with the usual procedure. I imagine that Googling Rubber Fetish will produce a raft of sites. It's part of the general Femdom bag of tricks which the Age of Aquarius is said to be cosmically engendering but evolutionists will vehemently deny that. They don't think life has any components they can't explain mechanically.
I think, though I have no experience of such things, that loss of ego and identity is the objective. It allows the lady in the case to treat the sap as an object more easily. As "worthless" as Despina says all men are in Mozart's Cosi fan tutte which means "women are all alike". Dylan's "Baby can't be blessed till she sees finally that she's just like all the rest" is maybe inspired by that.
I presume it heightens skin sensitivity and tension and that the sap gets to meet the truly liberated woman in all her "ragin' glory". It's a libertine position and, as such, decadent. A sign of boredom with the unchaste female.
I have heard of the rubber suit being inflated and the ball being suspended from the ceiling.