Sister story to "Ookami Papa wa Hitsuji Tsura shite Yatte kuru."
A man still getting over the emotional fallout of his last relationship has been single for five years and pining for his best friend. One afternoon, when he's picking up his nephew from daycare, the robotic teacher at his daycare calls him out on his lovesick expression - and then begins to insert himself into his life.
Sensei wa Butchozura Shite Yatte Kuru