Having grown up on a dairy, I can say with a fair bit of certainty that you'll have a hard time finding a farmer willing to let you try. The health code violations alone would be enough to shut him down for good.
I used to think about trying it with a calf, they'll suck anything, but was too afraid to try. When they don't get any milk they jam their heads into the udder to stimulate production. I don't think having a calf head but you in the groin would be much fun either.