@
Stag, I have been mulling and contemplating your testicles and may have now the best serious answer and solution.
Kids in nappies are prone to Nappy Rash. They have very thin soft skin and pee in their naps as well, so as bad as it gets.
The Zinc and Castor oil barrier ointment sold for kids is outstanding for nappy rash. I have a part pot of it here and I tried it on cracked hands and it really sticks as well as keeping the skin soft which products like Vaseline dont. They stop chaf but pull oils out of the skin.