Based on the manga by Koume Keito.
In this alternate reality sex is not a reserved theme—it is not even a
discrete thing. This is due to the existence of female and male pollinic
humanoids, who travel just like pollen via the air and when they find
a receptive human they start their process of fertilization—or at least
that’s what they intend to do. It’s just normal to see them everywhere
and all the time during their season, and there are only few ways to
avoid them, so almost everyone is caught up in the pollinic humanoids’
mating allergy.