Just make sure you find someone who really knows about the kink. Lots will say they’ll help just wanting to get some jerk off time in. Ask lots of questions expect detailed answers with some points of reference from the Dom. And do some of your own research.
ideally as prior stated:
Natural Pregnant transformation
Pumping to bring in milk
And no more bra use (this takes a long time) are really the only way to get size increase. Supplements can be suggested but really don’t work and you always risk side effects.
figure out if it’s just about the tits and milking for you. Or if you want the entire animal factor treatment. There is much more to it all than just the tits udders.
enjoy your exploration.