When you have her in the yard, it is a small yard so she can't move back or forward. You stand in the middle. She can not head butt the calf as you are there. You have the whip and you are in between. You are there to protect the calf. Twice a day, so 12 hours a part. It is a lifestyle choice if you can not be there for your animals then question if you should have them.
With our cattle crush. The cow goes in. You can restrain her head if you wish. Then you open the bottom of the gate. She can not move forward or back. You put the calf on to suck. If he won't suck you have to put him on. Your legs behind, push forward with your legs, down on the neck, up with the head, open the mouth, put teat in mouth and milk.
If need be use a rope and tie the leg back so she can't kick, but I find if you do it gently and growl if she goes to kick and touch the udder and then gently milk you don't need the rope....and I am taking about beef cattle who are not milked usually.
If you have not milked the cow by now, you must be getting towards the day for it being too late, surely?