Thanks for the query.
Excess moisture on tail bone is a non specific condition.
moisturizers wont help you.
Probably you can apply some talc powder.
This will keep it dry.
Dryness in this area is necessary as excess moisture can cause fungal infections.
powder may provide you some relief.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
please meet a dermatologist
if it persists.