All the wishes and desires are natural if both wish them and desire. That's why there is nothing to be ashamed of when you use some sex toys in your sexual life. I would rather say it is a natural need of a person. The traditional idea is that a man should use a
strap on for a woman as an additional way to excite her, but few men say that they really enjoy anal sex with the strap-on as well. So when you both are ready for new, go ahead with it.