Sub Slave Cow

I am milked twice a day, my boobs grow big and fill up and start to hurt, then my master will place me over the stool, and place the milking machine on my teats. Sometimes he will suck some out of me, and usually about 4 to 6 times a week men come by and he lets them nurse it out of me. If they don't get it all, I start to fill up again, but with the remaining still in my udders, I hurt and even cry from the pain. I beg him to put me on the machine, but he sticks to a strict milking schedule. Sometimes he allows me to suck some out of me. I am nude all the time, the men who nurse on me all finger my privates while doing it, some pay him extra to sex me.