Top definition
When you're having sex with an ample-boobled girl, it's possible to time your thrusts so that her jubbs move in perpetual opposing circular movements.

Next time you're giving your girl a bit of playtime, it might be worth mentioning this to her when you see this happening.
"Honey, look! We made the Van-Groeshner Effect happen! Wow!"
by cosmictoothfairy March 11, 2010
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