Inma no Mikata!

Masato might be an unemployed, virgin bachelor, but ever since he was a kid, he's wanted to do something that could benefit the world. With it looking like he'll never achieve his dream, Masato's approached by two sisters who might give him that chance. Tomoe and Ayano work with a succubus organization seeking pure human blood and Masato is one of the last remaining pure-blooded humans in existence! With his essence carrying immeasurable value to succubi, they hire him to suck every satisfying ounce of seed straight from the tap. But once he's revealed to the greater succubus public, will he have the will and strength to accomplish his goal?

(source: FAKKU)