Well, I have tied someone up and found that quite erotic; but then trying to whap 'em - well, no. I mean, I did, a few times, but I really couldn't bring myself to go on. It was just - wrong. But then in the context of that relationship, I was usually submissive to him, and I didn't feel he really wanted to be hit - just wanted to see what it was like. So I couldn't carry on with it on the basis that I was pleasuring him, and I just had to stop.
But, I think I could get into it, sometimes, switching with a partner who genuinely wanted to submit and was turned on by receiving pain - sometimes.