How to train my 3 year old green cheek to wear a bird diaper suit?

I was wondering if anyone could give me advice on how to train my 3 year old green cheek conure to let me put one of those bird diaper suits on him? I tried an aviator suit when he was younger and he didn't like it. It may have been because it was a bright color. Also the fact it was a strange thing in him. I have a hard time keeping up with his poop when he's out of the cage. Thanks to anyone who answers!