Grace was uncomfortable when talking about how her father used to cane them. But she understands why he did. They still want him to spend more time with them. It depends on why you're caning. If it's a thrashing out of sheer anger, and you're losing control, it can be abuse.
Some people think that excessive caning without hurting the child seriously is abuse.
Explain your actions after you've caned the child. Hug or reassure the child. Say that you don't like what he did, but you still love him. It's not as if you're breaking their limbs. I use it only when I'm very angry and as I hit them, I'll explain to them why I'm doing it.