'Bananas are one fruit able to impart body to a wine, and they are frequently used as a substitute or addition to grape juice. Their own flavor, however, is rather pronounced. This can be reduced by discarding the skins, chopping the fruit into water and boiling for about fifteen minutes, during which time the pungent chemicals responsible for the strong banana flavor are driven off. The body which the resulting liquor provides in a finished wine is due to the presence of unfermentable compounds in solution - chiefly glycerol-like molecules, which give a viscous appearance.'
And I can attest what Allie says is right on. Just add before you clear if you think you need more body. reason is it will cloud it up some.
Just don't do it a week before bottling...remember patience X 3