[Katana]

it's Nonmilk discharge, as women our mammary glands fill up, especially during our luteal phase-- it is what causes the fluid retention and bigger breasts during luteal.. that is why your breasts are aching-- I think the fact that you've been massaging is activating them more and because of the stimulation, it's coming out. unless you're pregnant/given birth, it isn't milk.

"Nipples may secrete fluid when they are stimulated or squeezed. Normal nipple discharge may also occur when your nipples are repeatedly chafed by your bra or during vigorous physical exercise, such as jogging."

some women have some type of nipple discharge or fluid when their breasts are squeezed.. it's a normal thing. breast stimuli sends the message to the brain and the pituitary gland responds by increasing prolactin levels, and that causes the discharge.

http://www.aafp.org/afp/2012/0601/p1073-s1.html

the prolactin levels are what is making your boobies bigger

That webpage makes me wonder if the high prolactin is responsible for my absent periods too.