Why would kinkiness be immoral? It just sounds to me like asking whether it is wrong to eat spicy food? I don't understand what the potential problem would be.
Why no anal? Seems like a random thing to ban.
Why would God care? Seems like a rather petty concern for God. If I eat for pleasure, or play sport for enjoyment alone, is that wrong?
All uses of the body are natural. If they weren't natural then we wouldn't be able to use our natural bodies to do the action.
God also gave us legs, but we use cars anyway. Is that unnatural and immoral, if your legs work? Some people even drive for fun.
I wouldn't say that is a good test. How people feel about actions can be a product of upbringing. Eg: we are told certain things are dirty, so we feel slightly uncomfortable about them, even if they aren't immoral.