[Karuno Kamo] Tonari no Onee-san (Part1&2)

Aoi-san, the stacked neighbor whose chest dwarfs the boy beside her, shrinks young Taiki-kun down to pocket size and turns him into her personal plaything through teasing treasure hunts—hiding gachapon prizes across her enormous body and daring him to climb every curve before a five-minute timer runs out. Between rounds she toys with him, peeling off her top and asking whether he meant it when he promised to be her boyfriend, and his flustered yes seals a relationship where she gleefully vows to shrink him all over again once he's back to normal. A two-part size-play romance where the overwhelming size difference is exactly the point.