It was an ad campaign from the late 2000s to try to get kids to drink more milk in Japan: The tagline literally means "talk to the milk," as in, have a heart-to-heart with it, get to know it, it'll help you out! I wouldn't translate this literally. What is the context of the line? It's a trope in Japan, like in the U.S., that milk will help you grow big and strong. The ad campaign took it one step further and said "hey, milk will basically give you superpowers."
Hi! I noticed one of your staff members posted recently on Baka Updates about needing a translator for Kiss & Never Cry. I've actually been translating it for over a year for fun and posting the translations on my website, http://www.faceorama.com/pizza/, if you're interested, you're welcome to use them to continue the project.