Pen the dog next to the bitch so that she can tease him through the wire fence
thereby increasing his desire.
Do not let them run together, if she is not ready to mate, she may become aggressive,
and the dog could lose all interest in mating her and prefer a fight.
Always have a warmed glass in your pocket in case the dog slips out, should this happen catch
the ejaculate in your warmed glass and artificially inseminate the bitch.
If you have a Microscope ( An Essential tool ) check the Fertility of the dog
and the Ovulation of the bitch, it is a long time between seasons.
Once mated whether naturally or artificially stand the mating machine up on end
( with the bitch still attached ) at about 45 degrees to help the sperm gravitate towards the womb.
 

Problems that can arise
Sometimes people think that it would be better to have a strap to hold down the bitch,
my experience is that very often a strap pinches the bitches teats causing her to turn
handsprings on the machine, a soft rope is better.
If the dog is being difficult, walk the bitch around on a lead with the dog following her
until he gets worked up enough to mate her on the machine,naturally or even artificially.