Hello Moon Yau,
Could you be more specific what kind of DragDrop you like to implement - e.g. item reorder, dragging to another control or from another control, etc.
The initial difficulty in implementing the DragDrop is to get to the elements that you want to be drag sources or drop destinations. There should be a way to set the AllowDrop and AllowDrag attached properties.
Then it is a matter of handling routed events that can be handled anywhere on a parent in the visual tree.
Please note that elements that capture the mouse on mouse down cannot be successfully dragged because they handle all mouse events in doing so.
Could you please be more specific or ideally send us a sample solution with the accordion setup. I will be happy to help you with any difficulties you encounter.
All the best,
the Telerik team