Perhaps you might want to emphasize the playful loving aspects of sex and talk more about responsible loving. You might also want to give some thought to messages you will want to communicate to your pre- and early teenage children regarding masturbation. Many of us grew up with the idea that this very common behavior was a sin worse than murder. While being respectful of your own moral views, you might want to help your children place this behavior in a more reasonable perspective. You may want to help your children maintain their natural sensuality.
Many alarmed parents forget that their child likes to run around naked only because it feels good.
While running around naked may not always be an option, we nonetheless may want to introduce the issue of social mores gently so that the child will not completely lose the capacity to be sensual, to enjoy sensation, and to be in touch with their bodies. Our senses, after all, are the vehicle by which we contact the rest of God's creation. Finally, while having sex in front of one's children may not necessarily be a good idea, being affectionate with one another is. Further, there is no point to pretending that you are not sexual beings. Children eventually figure out what the noise coming from their parents' bedroom is about, especially when the door is locked.