You want to use the thinnest, clearest and softest plastisol available. I have a tall borosilicate beaker I use to dip my swimbaits in. If using a standard "medium" durometer plastic, I add a tablespoon of softener to it to thin it out and get it nice and hot and dip the bait to the end of the hook slot. You don't want to dip too much of the tail or it will impact the swimming action of the bait.