What did you do to be able to fuck Dr. Blight?
According to the wiki, if Ryoko’s request to lock her elder Thunder girl in a room is successful, she will give you an item to have sex with “Dr.Blight.”
Given Masuo’s apartment is mentioned here as a place to lock up Thunder Girl in a room and the “Mayscape Apartments” place to be added to the next update, that opportunity is likely to arise in the next update.