Third wheels tend to get a bad rap—but really, why should that be? Without their third wheel, tricycles would lose their balance; and who would put the three in threesome?
Yes, the third wheel is there to balance things out, and fill the gaps that might otherwise be left sadly vacant. When properly involved, a third wheel is anything but a nuisance—like in the case of this "third wheel," who's an absolute necessity to the action.
· A little MMF action (xtube.com)