You ever had to collect a sperm sample from an animal?
There is a certain "feeling" involved.
We had to dogs at university that were for students to practice every week, Tuesday afternoon.
They both *knew* when it was Tuesday afternoon. One was a rambo sort of guy. Had difficulty holding himself back at the sight of the glasses we used for collecting. I swear, he was quick to the shot.
The other one was more of the shy type. Needed a lot of calm sweet "feeling". One wrong move and he would recoil and you were done for the week.