Succubus Chase ~A World Where Drinking Semen is the Norm~

In a world devoid of humans for over 500 years... If succubi can't drink semen, they'll die... This is a story of trying to escape and survive on the run in such a world. Currently, the succubi are barely surviving by drinking stored semen carefully, but even that's running low... The protagonist gets summoned by a succubus into this world... Will he manage to escape from their pursuit?!