First, lets put slaveboy out of the way shall we, you don't want his hungry eyes on your body, wile you read, now do you?
tell your slave to undress, is he hard yet?
tie him spreadeagle to the bed, if you like you can blindfold him.
we want him nice and open for you, so make sure his knees are tied as far apart as possible.
Since one of the goals of this is to find out what makes your slave tick, we will keep an eye on his cock, if he is hard then he is enjoying what is being done to him (he doesnt have to enjoy it, but it is very valuable to know)
If his cock is not hard, it doesn't mean he is not enjoying himself though, sometimes teasingly asking if he enjoys it can be the best indicator.