I've played with a safeword, and without. To me it's all a matter of how well I know the sub. Take it or leave it. If your comfortable without, then stay without.

Back on topic.

I love to face slap, same as I like to punch. I just enjoy the taboo breaking act of it. Not to mention it causes a humiliation and breaking of emotions on her part. If your having fun doing it. Just have fun exploring the whys, and when you figure out why you like it. Let that be the reason it continues, cause in the end, your still liking it.

Have fun!