When a male loses his virginity. It is the male equivalent of "having your cherry popped." The term "blueberries" is used to refer to testicles, being "blue" from never previously having sex.
Example 1: "When are you finally going to pop your blueberries, bro?"
To come up with a complete non-sequitor in a conversation. The entymology of this word began on The Geek Show Podcast when panelist Leigh George Kade would be accused of completely derailing conversations with completely irrelevant information. One day, when he wasn't there, a fellow panelist decided to "fill in" for him and shouted "Blueberries!" for no reason.
It's caught on with the audience of the show and is a recurring declaration when an irrelevant, derailing comment is made.
Blueberries are the blue tasty round objects you find randomly in the forest. Some theorize that they are "berries" but scientist have proved that they are in fact homes of infant aliens.
Blueberries can also be to describe a really bad situation with a survival/success rate of only 1 to 100.000.000
Some dude: Did you see those blueberries near the forest? Man, if i had the time i'd make a blueberry pie.
Other dude: wtf man, why would you eat alien infants?
Some dude: Hey dude, you look like you are in some blueberries.
Other dude: yeah man, i don't think ill live to see another day, i'm in such a blueberry.