eight ballのようなどんな単語でも探してください。
 
1.
A woman with a very flat chest, such that it resembles her back. Only the nipples give it away.
The girl at the party was pretty, pity about her two backs.
DesDDDによって 2007年09月24日(月)
 
2.
A "twoback" is a woman with no visibly protruding breasts. See also: "flat as a board."
Lucy the twoback rarely goes on second dates.

"Is that a stop sign or a twoback?"
snowshoesnyによって 2009年09月26日(土)