Sure!
CDQ's are great fun and are required to take a PrC such as Shifter.
The process is easier if you have been keeping a character development thread that shows clear progression and viable IC reasons to take the PrC.
Once you are ready to start taking your levels, you need to resubmit your character approval thread with additional information showing why and how your character would take the PrC. Once that is approved, check the CDQ forum and find a GM that you like and that has additional slots available and leave a post explaining what you would like. It can be as detailed as you want, or it can be a generalization, leaving most up to the GM that runs it.
After you are approved and the GM gets in contact with you to schedule the CDQ and discuss details, you have great fun with it and hopefully at the end you can take your requested PrC.
Hope that helps.
