Ai no Su e Ochiro!

The low-class gossamer-winged butterfly Tsubasa happens to see Sumiya Nagumo, the son of a distinguished tarantula family. Saved by his words, Tsubasa holds admiration for him. From a single glance, he wants to meet him, and he enrolls in Sumiya's school: Seihoku Academy, where only the elite gather. However, hardships due to his low class awaited him there. On top of that, Sumiya—his only hope—tosses him aside, saying, "I hate gossamer-winged butterflies." Tsubasa had believed that he would be acknowledged, and becomes depressed. At that time, he becomes trapped in the web that Sumiya had laid, where he's injected with an aphrodisiac venom and is held down...?

(Source: Hakusensha, translated)