This manga is getting silly even by its own standards. Obviously the BL manga would have been a less painful option, although I question the MC's sanity for letting her into the house to begin with.
Mao or Sayuri could've easily won over Keiki if they could've managed to dial back the crazy by like 30%(Sayuri) or actually be completely honest with her feelings instead of hiding behind the BL manga/"It's just a joke!"(Mao) excuse.