Semen King! ~Arthur Ou mo Entaku Kishi mo Majo mo, Ore no Seiken de Keiren Soku Iki!~

What if Arthur, Merlin and the Knights of the Round were beautiful women?
The protagonist is a modern day high schooler with a strong libido but his life is boring and friendless. One day a curse reaches his ears as if riding on the wind. In the next instant, he tumbles into a hole.

He opens his eyes to see a woman of unparalleled beauty. As she talks, the situation becomes clear. Her name is Queen Artura... It's utterly unbelievable, yet he's fallen in love already.

In her castle there are more beautiful women. Bishoujos everywhere. This was never in the legend! The protagonist's libido flares, but he knows in his heart he's on borrowed time. Lacking the strength or the battle smarts of Artura and her Knights of the Mons, he knows it's a matter of time before they find out he's useless. Then what?

Meanwhile his libido is bursting with anticipation... That's when he discovers the potions lab of Artura's trusted sorceress Merlynne. He takes an aphrodisiac that quadruples his sperm count and then some!

Pants bulging like never before, the protagonist makes his destiny.
In this alternate world of Queens and Lady Knights, he will be...

The Semen King!

[From DLsite English]