The tendency of otherwise straight girls to decide that they're gay during their time at Smith College, only to realize that they're not shortly after graduation. See also smithies
I knew this great, beautiful girl who went to Smith. I had a huge crush on her, but she was gay...or so we thought. Turns out she was on the four-year-plan, and now she's in New York and has a *boyfriend*!
by Beebo McSnark April 18, 2003
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The extremely safe method to not have children, consisting of waiting four years with a boyfriend/girlfriend before having sex. Also can be taken as 1 base for every year.
Mike: "You hit that yet?"
Skeeter: "Naw man, only half way through that four-year-plan. Sho aint gonna be paying no child support though, YADADAMEAN?!?"
by Mixmaster Skeeter January 24, 2006
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