Milk Hunters

From the introduction: Welcome to the world of Pretty Cure! Well, kind of. This is actually the world of Kuroyuki's Milk Hunters series, which has just a few small changes. See, Cure Black and Cure White are being affected by a dark energy that's draining their power, and the only way to recharge it is through drinking cum. Specifically, the cum of a fat, greasy creep who's known only as "Senpai." Yeah, this is one of those worlds. You will appear on the morning that the Pretty Cures discover that their power is being drained, and what they need to do to recharge it.