Don't bullshit at all and tell him right away, the next time you see him. The facts are he is staying at your place, which might be too invading for you and smothering. If the tables were turned, I'm sure you wouldn't feel like you are smothering him, so don't think that he will react badly, just think about what is acceptable to you if he were to say, "I need my won space for a while" or "I need to get some things done." Everyone is different and he is probably the person in your life that knows you better than most, so you don't want to surprise him with a "talk" you want to tell him straight away, the next time you see him. I suggest saying something that is more straight forward and less interpretive, like: "I need you to stay at your place more often so I can get more done at night and enjoy the time we do spend together more." This way when you do see each other is less mechanical or domestic and more impulsive.