Shiranai Koto Shiritai no? The Animation

Synopsis

Pla-Pura
When the protagonist's grandfather, who runs a plastic model shop, falls ill, he ends up taking over the business. A regular customer, busty plastic model otaku Risa, appears as a part-timer! Thanks to the strict but reliable Risa, the shop reopens safely, and one day the protagonist discovers a solvent his grandfather made himself. As the protagonist and Risa are chatting after work, he is surprised when Risa starts to get changed without any protection, and ends up spilling the solvent he has on her body! As the protagonist panics, Risa's mood changes and she becomes sexier! As her whole body throbs, the busty girl begs him, "Please... calm me down?" ♪

(Source: Pinkpineapple, translated)