Yes there are.
For me the dog penis is absolutely beautiful. It is visually stunning I love just watching it. Then the knot usually has a very pleasant smell and the penis has a really pleasant texture when you suck it.
Obviously I love feeling cum shots in my mouth.
If it is possible I want to see the dog enjoying the experience, so closed eyes, relaxed mouth,... But not all dogs look at you as you are working on their penis.
I mostly do mouthfucks and I like the feral energy the dog puts into thrusting in my mouth.