Definitely have the slave clean your apartment, Sir. Find out if your slave is into chastity. If he is, make sure the slave cannot jerk off the whole time he is there serving you, Sir. It might be best to talk to the slave first, before inviting other people over though.

As for sleeping arrangements, Sir, I would suggest as apparently others have, somehow tethering the slave to the foot of your bed. Tying him there, or if he has a collar or something that you make him wear, just tie/chain him up by the collar to your bed. Make sure to give him your dirty sweaty socks to sleep with, Sir.

Tying/chaining him to the bed is also a good way to keep him out of the way while you 'relieve yourself', Sir. That way you know he won't be able to go anywhere or get into anything in your bedroom, and he won't be able to see you jerking off. If he makes too much noise, just stuff one of your dirty socks in his mouth and use rope, tape, or another sock to make sure it won't come out.

I guess it's a personal thing, but in my opinion Sir, if he hears you jerking the worst thing that's going to happen is he will wish he could help you with it and being tied to your bed will make sure he is reminded that that is not his place, Sir.

To be honest, since he's your slave if you were to allow him to service you sexually it wouldn't make you gay or anything. You might enjoy it, Sir, you'll never know if you don't try. Gay men are usually really good at giving blow jobs, since they actually have penises of their own and know what feels good and what doesn't. Straight Masters use gay slaves all the time for this, it doesn't make them any less straight, it's just another form of the slave worshipping the Master. If the slave is locked in chastity of some kind, it might make you more comfortable since you'll know you're the only one allowed to enjoy what's going on. :)