Spike it dye will bleed like crazy, so you'll have to apply it on the boat and then toss the bait afterwards. I use it a lot to add chartreuse or red tips to baits.

You can also put about 5 drops of it into a bag of plastics, along with a tiny bit of liquid scent and it will dye the whole pack. You can make some cool colors this way, including the famous pearltreuse. Do not add very much though.