Place her in an escape proof plastic container with some holes to ensure breathing. Put just enough water in the container to come up one half the sides of the boa. Don't over do the water or she could drown. Leave her in the container for several hours. You can just place the container in her cage. After soaking the stuck tail skin may just come off on its own during the soaking or with very gentle rubbing with your fingers. Don't pull the skin off and repeat soaking until it comes off very easily.
Shedding is a constant, on going process that actually starts all over again after the last shed. Maintaining proper humidity will promote easy, one piece sheds. I wish you all the best with your boa. Hog Islands are great. I have a pair of them. Bill
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...three years ago it was just another snake cult...
The Retic is King.
Anacondas-the other Dark Side.
Afrocks-the dark side of the Dark Side.