How can I double tap a Sprite?

Sure, just remember the Clock1.SystemTime of the TouchDown and subtract it from the Clock1.SystemTime of the corresponding TouchUp. If the difference > 3000 then do whatever.

If you want the whatever to happen after 3 seconds even if still held down, you would need to devote a Clock to this. Name the Clock appropriately, to not go nuts with complexity.
Start the Clock at TouchDown, and disable it at TouchUp. Each Timer event, do the SystemTime check.

The thing is that I am still going to need the blocks in sprite.dragged because if I put those blocks in a clock timer it won't work because they contain Variables from the sprite.dragged.