IŽll go first:

In German writing the words for master and heart differ in only one letter.. "Herr" and "Herz" so I call my master "mein Herrz" which implies to us both the respectful "Master" and the term of endearment "my heart"... And anyone else only hears the "my heart" so I can call him thus anywhere and anytime while we will always know that this is more than a simple pet name. Only in a session I will sometimes drop the "z" and make it a straight "master"...
I love this very much as he is all, my Master, my Heart.. and the Master of my heart ;-)

Deigja