Help! What do I do with this Bansai off-shoot?

I have a Bansai tree that sits in my computer room, near a window...it's recently grown this huge off-shoot, and I'm not sure what to do with it! The wall next to it is somewhat support it right now, but I worry it will grow too large and break.

Should I prune it? Thanks for any advice!

Edit: Picture: http://imgur.com/F9Ej1