Dr. Ginkaku and The Guinea Pig

Dr. Ginkaku's is a genius with a wide array of knowledge, but he's also a germaphobe who hates people and is very much a loner. However, he receives a great amount of support from his skilled and talented assistant, Aki Kayanoya. Even though Aki respects Dr. Ginkaku, he's troubled by how the doctor is always using him to test out the naughty machines he's invented that make him squeal in pleasure. Aki dreams of working with Dr. Ginkaku to help rebuild the city, a major research project the doctor abandoned long ago, but will it come true...!?

(Source: Renta!)

Notes: Includes four extra chapters, three are from the Kanzenban edition published in 2020.