It's mostly a mental connection.  Yes, of course it is tremendously sexual but without the common bond of master and slave it's just kinky sex.

The burden of pleasure lies squarely on the slaves shoulders. I am responsible to inflate and satisfy your pride and ego as much as satisfy your demands. 

When a slave approaches a Master with hopes of beginning a relationship,  it it with the presumed understanding that they are members of two classes of society.    Owned and owning class.  The slave and master may not outwardly display this to the world but we both know our roles.  Entitled and indebted.  

?You,

???????? An intelligent Master, capable of enjoying all thats good in day to day life.? Stable, smart and confident, you are as normal in the vanilla world as I am.? As the conductor of the relationship you take us to the depths of your dominant mind and back.? Hopefully you savor the element of training as well as my display of it back to you.?? A masculine productive guy all day long,? you love that I'm thouroghly whipped and wrapped around your leash.? You recognize my need to be my productive, masculine self and truly enjoy the fact that you own it as well as my well trained subjugance.