1 definition by gretaaaaaaaaaa

Two trains on the same track are moving towards each other, each at a speed of 40 miles per hour. On the top of one train stand 50 naked guys with boners. On the other train stand 50 naked girls who are horny. What happens to the ones that don't fall off when the two trains run into each other is called 40th base.
Damn, i just got an orgasm from 40th base....it sure was pleasureful...
by gretaaaaaaaaaa July 27, 2008
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