When you are fucking a girl and when you are about to cum, pull out, tell the girl to spin like a top, and you leave a nice trail around her waist. Experts can attempt the prime meridian or the tropic of breast cancer.
I almost pulled off an equator but the girl didn't spin fast enough.
by equatorbator April 24, 2006
When a Tan Line on a pen15 seperates both halves of the Penor. For example one half is tan the other is Albino white.
"Dude that guy's equator was so embarassing"
by BlackDogz February 16, 2009