A estimation, often influenced by inebriation or equal mental hinderance, of a woman's observed bra size from a male perspective. Often used/found in places like college bars, night clubs, gentleman's clubs, etc.
Chelsie says:
Urm it's like a train station and a train goes into the station and the nipple is the train and the boob is the station
ALSO
Plantation is where seeds are planted to create plants and a nipple is like planted to create a boob.