I totally agree with Thrax, this is should include couples as well.
One thing that struck me is that as a couple, we do have rules -- but, so does our single male. I'm sure, or at least I'm hoping it's been mentioned before -- I think it needs to be a mutual agreement, just like it would as if we played with a couple.
I don't know, we've only had one single male that we play with so we can be quite ignorant on this subject. We've always treated each other with a mutual respect. We're not so vain and arrogant to think this is just about us. We, as a couple need to think of his needs, too. I guess what I'm trying to say is that he's not there to just be our slave and do what we want. We want to make sure he's happy as well and that we've filled his wants and needs at the same time.