Louisiana’s Royal Teeth haven’t been playing music together long, but listening to their EP “Act Naturally,” you get the feeling that they’ve been horsing around since birth. On “My Donna,” the sextet’s chemistry is undeniable, the harmonies effortless. In fact, it reminds me of the tea parties I would host in the backyard as a kid. I’d wear my prettiest white dress and sip water from a tiny porcelain cup underneath the trees with my best friends: Teddy Ruxpin, a few Little Ponies, and lamb. If I was going to start a band, I’d want them to be in it. And I’d hope our songs sounded like this one.