Similar to faghag, an otter plotter is a woman who has a close friendship with an homosexual. In order to be an OTTER PLOTTER, however, the homosexual man must be an otter. Which means (1) that he must be masculine, and (2) he must be less hairy and generally trimmer in shape than a BEAR.
You know that manly, in shape gay guy that works at the gym? The one that doesn't really act gay? Well (insert female name here) is his otter plotter! THATS why they're always together - she's totally single and you can still ask her out.