Bootlicking is sometimes seen as something as you either love or hate, there is usually no in between. But on the other hand, it is up to the Dominant to decide if the submissive should lick the boots and how.
Bootlicking can be a very intimate and erotic activity and very intense from the perspective of power exchange and humiliation. There is a nice visual appeal to it, in my opinion, and humiliation aspect is also something that can be a turn on. Boots are as you probably realise by now worn and that might call for some safety measures.
I would not recommend you to order your submissive to lick the sole of your boots unless you want one sick puppy the next day. The soles are in most cases filled with stuff that have been transferred from the street or the pavement. Using new boots would be one solution, but then the bootlicking wouldn’t have any real purpose, would it?
Boots with a long shaft are good, because there’s a lot of surface that has to be cleaned by the tongue of the submissive. Female shoes with straps might be enjoyable on the Dominant side because you will feel the tongue against your feet when the straps are being cleaned.
If you want to give your submissive an experience that talks to more senses than just a tactile feeling, then add some nice shoe polish before the bootlicking activity is going down – Be sure to check that the polish is non-toxic. Another thing you could do is to rub your boot with a lemon or something that has a bitter taste. That will add an extra challenge for your submissive to work with.
Who said that bootlicking going to be easy?