If it's only the end bit you probably don't need to soak him (a lot of the tail, then do soak). If only a very bit at the tip a warm wet facecloth around that area for a few moments and then let him draw his tail through the cloth in your hands, apply slight pressure and off it will pop. Good eyes for catching it! It's important that stuck shed never be encircling especially in the tail tip area as it can permanently damage their tail.