There's something i didn't understand when this chapter was released and still don't under...

There's something i didn't understand when this chapter was released and still don't understand even with the English version.. What is that infusion? It's just to increase the energy and stamina, right? I don't think it's aphrodisiac as some people say.. Aphrodisiac works in a different way i think. And i think nakyum is confusing his real feelings with the effect of the infusion. Man, your heart pounding and your hands trembling are you falling for Seungho, don't delude yourself thinking is cos of the infusion.. but i can't blame baby nakyum, just as seungho, he doesn't understand his own feelings