When you finish eating your cereal and take the leftover milk and pour it into a container labeled “Sweet Milk”
Reminds me of my cousin. Always went to this friends house after school. They had something called “sweet milk” and he loved it. Then he slept over. Sweet Milk is when you finish your cereal and pour your leftover milk into the Sweet Milk container.
You Gotta Taste The Sweet Milk Before You Get The Cow!
Stemming from a mix up of the two phrases, "Before you buy the car, you gotta take it for a test drive," and "why buy the cow when you can get the milk for free," this phrase is interchangeable with the former. You would say this if your friend wants to remain abstinent until after marriage.