A viscid whitish fluid excreted from a homie's reproductive tract consisting of spermatozoasuspended in secretions of accessory glands after a hot sweaty session of man-to-man love.
Two men who have shared a particular sexual partner consecutively, although not necessarily in quick succession. The essence is, your Milk Brother was the last person to have slept with this particular partner before you did. (Like blood brothers have shared blood, milk brothers have shared milk, at least symbolically.)
Guy at Party: "Why does Javier's girlfriend get all tense, but also kinda flirty whenever Claude is around?"
Guy 2: "She used to bang Claude. In fact, Claude and Javier are Milk Brothers"
The badge of honor affixed about the shoulder of a caring parent by a baby during burping. Like snowflakes, no 2 milk brooches are alike. These decorative regurgitation signatures are commonly gifted to the recipient prior to a special night out on the town. Some think that it is the baby's way of helping the parent look their very best just before departing. Sometimes a milk brooch can morph into a milk necklace, but we won't go there.
I was wearing an interesting milk brooch today on my favorite grey sweatshirt. It looked like an octopus swimming diagonally. I got several compliments on it.
To declare yourself a "Milk Bro" with another buddy, the act of intercourse must take place with a female on the same or separate evening with the lack of a contraceptive. Note: Filling her tank is a crucial step in deeming yourself Milk Bros.
You slept with _____ ?? So did I bro ! Did you wear a dome? Nawh me neither ! So you filled her tank? ..... High fivemilk bro ! We're Milk Bros !