Complex sentence: Soon Noah is invited to a party to have sex with his supposed girlfriend Marisa (Ari Graynor) who uses him only to get oral sex, she agrees to have sex with him if he brings her drugs to the party.
Split into simpler sentences: Soon Noah is invited to a party to have sexual intercourse with his supposed girlfriend Marisa (Ari Graynor), who up to that point had used him only for oral sex. She agrees to have sex with him only if he brings her drugs to the party.