Apparently Salvador Dali was a practitioner:

According to Roger Peyrefitte, Dali’s invariably well-informed housekeeper, …

Things of this kind aroused Dali’s admiration. He compared the vagina to a cauliflower and commented that it was Nature’s ruse to ensure reproduction, but that the true organ of love was the anus. In the vagina one might poke about without really knowing what one was up to, but in the arsehole there was no room for any such uncertainty.

Dali made these observations in a conversation recorded for French television (though of course it was never broadcast), and declared roundly: “The most important thing in the world is the arsehole.” For Dali, the body no longer had any secrets. He had devised a special procedure (which interested Roger Peyrefitte greatly) to ensure that a woman on all fours would present her anus to greatest advantage: he would place a spirit level on her back, and when the air bubble was precisely in the middle, he claimed, her anus would flower in its full glory.

On occasions, he would ask female visitors to sit on a bed of moist clay with their buttocks parted, in order to take an impression of their orifices. He would subsequently frame the impressions, adding the names of the ladies in question. Supposedly -and this again demonstrates Dali’s tirelessly investigative cast of mind - the anus has thirty-five or thirty-seven little creases which are as unique as fingerprints.

He regretted that he could not account for the variation in number, but noted that it had nothing to do with social class, and that thirty-fives were as likely to be found among the aristocracy as among the working classes. Only the backsides of identical twins had exactly the same pattern and number of creases. He conducted experiments to substantiate his claim, and made the impressions of twins’ behinds into candelabra.