Onii-chan wa Oshimai!

Mahiro Oyama was just a normal erotic-game loving dude...until he woke up one morning as a woman! Turns out his mad-scientist little sister, Mihari, tried out one of her new experiments on him...with a disastrous outcome, as far as Mahiro's concerned! But Mihari is as determined to study him as he is determined to go back to his shut-in, game-playing life, and one thing's for sure...life is going to get a whole lot weirder from here on out! *5th place of Tsugi Manga Awards, Category Webmanga - **Retail:** (Direct Retail From the Mangaka)  (https://www.melonbooks.co.jp/circle/index.php?circle_id=3753)  (https://ec.toranoana.shop/tora/ec/cot/circle/2UPA116P847KdC6Rd687/all/)  (https://www.dlsite.com/home/circle/profile/=/maker_id/RG40614.html) (jp)