As usual words are better than 1000 words.
I simply added to my Pin Tail Soft Bait a little tail shaped from a fiberglass foil. After the soft bait tail is passed through the hole of fiberglass tail, I melt the soft edge with a Chef Torch to fix the fiberglass tail in position.
It is not exactly an idea of mine, but it comes from Imakatsu that shows here his prototype:
Soft bait swimming is exactly as showed ... it wags its tail
Ciao.
Cami