Harem Fantasy! Chuunibyou ga Yuusha ni Natte Osananajimi ya Hime, Maou to Amaicha H na Kozukuri Bouken♪

Synopsis

One day the protagonist, a hormone-addled mess of teenage fantasies, is transported to a truly fantastic world. Together with his beautiful childhood friends they accept the princess's request to save the world. Everything here is imbued with magical powers that is enhanced by imagination... that is to say, basically, his ecchi thoughts manifest in the real world! How can he NOT go on a babymaking journey!? Thus, the hero's (infamous?) adventures shall be transcribed for history... Gather strength! The spoiled sweet ero harem life begins now! (Source: dlsite, edited)