Zubunure Seifuku Musume ni Biyaku o Nomasete Renzoku Nakadashi ~Rumi-chan wa Yokkyuu Fuman~

Every time it rains, Rumi shows up behind the penny candy store. As a regular customer of the store, a guy attempts to get to know her but she is always blunt with him, preventing further action. In order to steal her heart, he spikes a penny candy with aphrodisiac.. (Source: DLsite)