Original title: 異世界孕ませハーレムパーティー ～最弱の解析スキルが異常発達してエッチな弱点を丸裸に！最強の爆乳冒険者たちを肉便器化！～
Our hero had nothing going for him until the day he was lucky enough to be reincarnated in a fantasy world like he'd always dreamed.
Unfortunately, he didn't get any of the special powers that usually entails, so he was still just an ordinary guy.
Eventually he was subjected to a magical drug trial by the ill-tempered mage Luka -- and it worked! His power awakened! The power to see a girl's most sensitive spots and fetishes. A rousing success!
With his new ability, all the beautiful adventurers in the world can be his!
Download Isekai Haramase Harem Party~ Saijaku no Kaiseki Skill ga Ijou Hattatsu Shite Ecchi na Jakuten o Maruhadaka ni! Saikyou no Bakunyuu Boukensha-tachi o Nikubenki-ka!~ from k2s or fboom for free.