23:59 onward - this is how I eat asshole to get maximum tongue penetration by opening my mouth and sucking against her anus. This is a total act of trust because you never know what may plop out, especially if she climaxes hard. Also, the taste is more intense inside the rectum.
In my experiences, women are 100% more horny when on their periods. I had one woman I met on craigslist ask me to swallow her menstrual fluid as I was rimming her (I prefer anal when with females). The smell of a woman's pussy and ass while she's mensing is an aphrodisiac, a very heavy, musky and sexy odor.