How do you think society would develop differently if at age 16, without fail, every male human supernaturally received the knowledge necessary to summon a 'succubus' with no strings attached?
Specifically, the summoned 'demon' would only exist in the world to satisfy its summoner's sexual urges, and would vanish after a set period (unless extended via another 'summoning') or if it was put to work in some other capacity. The summoned being is totally enthusiastic about its role and simply cannot hold ill will towards its summoner. The means to summon it are trivial: a quiet place, a short incantation, and a few drops of the summoner's blood - other than having to bleed a bit, there are no drawbacks and no ways to interrupt, disturb, or detect the summoning apart from physically being there to mess with the summoner. Females, intersex people, and males under the age of 16 simply can't summon them, and the 'demons' will not interact with them if present.
Note that I'm only using the terms 'succubus' and 'demon' because they describe the image of what I'm talking about. The actual summoned beings have no tendency towards any sort of behavior except sexually pleasing their summoners, they don't come from any sort of cosmic underworld and they don't have supernatural powers. They may, however, have a slightly inhuman body, coming in unusual skin/hair/eye colors, possessing horns or fangs, etc. (see pic related)
So basically, this is a roundabout way of asking: if all men had their sexual needs taken care of at will, how would society change? What role would women fulfill in this society? Is it better or worse than the world we live in?
Let's assume it starts happening tomorrow.