Koyanskaya of Light

After taking a break and drinking some tea, you had this not really small problem between your legs called "raging boner". For some reason it just doesn't calm down. And after that you hear that someone stole some kind of potion from one of your Servants, Qin Shi Huang, and they are furious about it. By pure coincidence you know one Servant that already drugged you once, so you decide to check her out just in case. Entering Koyanskaya room, you see her very smug about something, sitting at her desk with a little flask in her hands...