Humanity is doomed because of succubi
The first two answers in the anatomically correct succubi question suggest a parasitic approach to the concept of succubi which snatches off human organs, either the tongue or the vagina and feed off blood and human sexual excretions.
Those answers suggest that in both cases the succubi reproduces by infecting other humans through vaginal or oral sex.
Humans are already highly sexual creatures and sex has always been kind of the center of all our societies where sex is either something seen as religious or an act to empower one's nation through reproduction. For the very sexual nature of humans most cultures have their own sexual hygiene and dogmatic beliefs or behaviors.
But most importantly prostitution, not every country has brothels but prostitution is a service spread across the entire world. This to prove that sex is not just a basic need for healthy humans but affection too.
Now given the idea of succubi increasing their host sexual desires even further though hormonal manipulation then we have the perfect recipe for a giant world wide orgy.... cough
Jokes a part, it seems that with this concept humans would likely meet extinction by infection, where real humans exist no more as they get infected with the succubi parasite.
So, when every human being on the planet is infected with the succubi parasite... How does evolution keep this going?
To make things more specific I would prefer the second answer the question I linked as reference.