Necropherris

Seeing living people for the first time in a long time, the undead are filled with the desire to procreate. The undead girls are so excited that it is hard to believe that they aren't alive, as they flock to the erect meat poles. They try new positions one after another, from bareback, to cowgirl, to missionary, as they try to squeeze out every drop of sperm. The men are treated like livestock, as they are forced to mate repeatedly as breeding objects, and the sex continues all night long...

(Source: Toranoana, translated)