Koi no Mahou wa Jitsuryoku Koushi!?

The protagonist (unsurprisingly named “Takuto”, again) is met with misery each time his childhood friend Chisato forces him to drink strange potions as per her strange scientific experiments. When her shenanigans has reached the last straw, Takuto forces her to down it herself, only to realize that this latest potion seems to be one pretty potent aphrodisiac… and the rest is history.