the tail should swim when you drop the rod tip and the bait just falls.Tip it with a crappie nibble. Don't be afraid to also try other bait types like tube,spike tails and such.
Take a look at this little lure...its a lure I catch a lot of fish on when I need a little extra finesse. I use the rainbow trout color and tip with a chartreuse chromaglow crappie nibble,
Lunker City Fin-S Shad | Bass Pro Shops: The Best Hunting, Fishing, Camping & Outdoor Gear
Berkley Powerbait Ribbon Tail Grub has by far the most tail action at the slowest retrieve of any grub I've ever used and I've used plenty. Walmart and Dicks sells them among other retailers, but be sure Ribbon Tail is in the name otherwise you'll be buying the wider tail Power Grub which is like any other grub you must retrieve faster to get the tail to flutter.
Used it today for over two dozen fish of different species until a pickerel bit it off.