Haven't tried it, but I decided to avoid this method and use human grade food coloring instead. I worry that the koolaid would provide flavor to items that should not be ingested. "Hmm shreds like wood, tastes like pineapple" this is just my opinion.
I would agree with Solo - it is NOT recommended to dye wood with flavoring. You're encouraging ingestion of the wood, and potential crop impaction that could lead to extremely expensive surgery, if not worse.
Please refer to these threads about safely colouring wood for parrots: