I inject the nibbles inside the tube using a 3 cc syringe. For 1, it increases the size of the jig, making it a bigger snack. 2, it adds a "flavor" to the bait, making them hold on longer, long enough to get hooked.

Now this is just my opinion, and after saying that, I still catch fish even if I forget to inject my nibbles.

BTW, I only use chartruse nibbles.