I love the way he furrows his brow.
We are still learning, but at a much faster pace now that he's getting older. 
@jengosmonkey If he can walk past her in a crate, poor boy is being teased ! Separation means that - being apart. Separate rooms if not separate houses, and walking them together ?????
I had a very experienced boy who would never mount a bitch until he had seen her defecate. So Marvin and I, or one of us with the owner of the bitch, would take them both down the lane alongside the house until she did.
THEN we would come back to the garden / house. But in single file, with Curly following his lady-love. It was important to keep a distance.
On occasions we never made it and Marvin had to sit in the hedge alongside the road, with his legs out into the carriageway, superintending the mating (holding them straight) while I directed local traffic - farm carts and tractors mostly - around him. One time an owner and I made it to the back door, but the mating took place on the doormat.
It wasn't easy to convince owners of visiting bitches of this fetish. . .
But you be careful - and don't tease the boy unnecessarily 😍 😈
