Technically Reggie hasn’t seduced anyone. Arguably Maddison seduced herself. He’s just endeared himself to Alex by managing to not be a total dick for upwards of 180 minutes. He’s probably underestimating his sister’s circle of friends as well. Still, he’s Reggie, so on some level he probably believes that. Regardless he’s got a legit shot at Alex & Maddison is just a matter of choosing to be an animal instead of a gentleman with a code of ethics.