It is OK to do. You should wait until your flow is not real heavy although you can engage in sex even when it is heavy. But when your period is wanning you need to put a towel under you to protect your sheets and enjoy. Some women are extra turned on when they are having their period. I don't know if it's hormones or if you know that you won't get pregnant. You and your partner need to get over the idea that it is blood. It is not the same. It is just the material you build up in your uterus each month in anticipation of making a baby. It is like building a little nest and since no baby is put in the nest, it is discarded. Loving sex is good any time.
