[Aji Pontarou] Nyotaikashita no de ♂ Tomodachi to Gachihameshite Mita~Hajimete Nanoni Oku Guri Sarete...Ikuuu!~ [WisdomWapiti]

A crash landing strands a lone researcher on an unexplored planet, where an ancient ruin yields a mysterious humanoid who soaks up knowledge fast enough to become the doctor's devoted assistant—right up until a strange fever reshapes his body into that of a woman, complete with big breasts and brand-new anatomy to study. What starts as a hands-on 'examination' spirals into a sweat-drenched first-time pounding, the freshly transformed scientist driven to cum over and over on her assistant's cock before a deep creampie raises an urgent question about cross-species pregnancy. An epilogue packed with kids reveals the answer, and just how humankind came to propagate on this lonely planet.