An obscure reference to something sexual, different for everybody. Many times refers to cum/breast milk.
I can't tell you what the secret milk is, it's a secret.
When you dye your hair a darker (and usually duller) color, to make people think you are either smarter or not as wild as they thought (because everyone gets tired of blond jokes, and rude pigs)
Girl: "I'm busted."
Girl's best friend: "Busted how?"
Girl: "My boyfriend saw my dye fading, now he know I'm a secret blondie."
The Pop Secret.
It's when your doin your girl doggy style and right b4 she comes to climax you (Un-knowingly to her) pull back a nice fat rubber band and pop her right in the butthole with it.
She was not expecting a pop secret last night when that rubber band snapped her in the butthole.
an anally discharged flatulence
Hey Joe I just let out a brown secret.
A cult that observes random people. They believe in Hyunbinism
he was observed by the secret society .....
When you blindfold your partner before sex, and then tell them to open their mouth to get ready for a load, you put a salty treat in their mouth instead (chips, pretzels, etc.)
"I gave my girlfriend a pretty nice salty secret last night!"
"Yeah, what'd ya give her?"
"Salt and vinegar lays!"
When a dark haired individual inexplicably grows patches of red or blonde facial hair in between one's normal black or brown beard- so much so that the beard remains a secret to everyone but the beard wearer himself.
Henry's stubble is rather elusive to the eye. They say it's a secret beard.