The pleasure of relieving your last lunch meal into a girl's mouth in a form of brown delight. After the delight is placed in the mouth, the female then proceeds with a wonderful, chocolate blowjob. This requires the male placing his hands behind the girls head, thrusting his hips foward, and forcing the shit to be packed in the back of the female's throat. Afterwards, the guy jizzes in the girl's mouth, creating the frosting. Swallowing is mandatory. Thus, a brownie surprise.
John took a shit in Jody's mouth then recieved a dark, creamy brownie surprise.
When a white married couple has a baby together and the baby comes out black
Jacob: WTF why is our baby black?
Catherine: .... This is a brownie surprise