The breasts that a "tween" (not a child, not a teenager) has. She would tend to show them off as if she thought she had large breasts.
Person A: Look at that girl, showin' off her tweentotz!
Person B: Who does she think she is, Miley Cyrus? Gross. Cover that up!
Person B: Who does she think she is, Miley Cyrus? Gross. Cover that up!
by littlewitch June 6, 2010
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