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I really don't see why it's a problem to draw an existing anime character.
There IS a thing called doujin, and people actually sell that stuff.
If it's Japanese material there is really no copywright violation in replicating it, even if you went as far as marketing your own manga of it.
But whatever, rules are rules...
Anyway, here's a question: What if your friend can't draw worth a decapitated gummibear, and you can't color worth a decapitated gummibear.
If you draw a thing, and your friend colors that thing, would either of you get decapitated for posting it?
There is a huge difference between drawing an
existing anime character (FAN ART) and copying an existing anime character
exactly as shown in official art (COPYING). Fan art is allowed, as long as you draw the character in an original pose, and/or style. You can't see a picture of Inu Yasha that you like, copy it, and then post it here--you just stole art. You also cannot copy someone elses fan art, or original art.
You can, however, draw a picture of Inu Yasha that you thought up yourself, in a pose that isn't easily recognizable as official art.
As for you actual question:
That could fall under two categories-- an art trade, and collaboration, depending how you want to phrase it.
If you draw a picture, then give it to your friend for coloring, it'd be nice if we had a copy of the uncolored version as well-- You can post it, you just need to state who did what. If you colored, you need to state in nice big bold letters that you just colored, and the same if you drew it. You need to give credit where credit is due.