I've had it several times in my life....both at home and with providers. In my own opinion, this type of massage really enhances the 'moment' like nothing else!
With providers, I believe that with this one, YMMV applies big time. I don't believe I recall seeing anyone 'advertising' it as one of the things they do. But I have found that some ladies enjoy doing this if that's what one wants.
Any other experiences out there?

I've experienced it. While I have had providers do it, I have yet to have a provider who knows exactly what she is doing. In almost all cases, I have had to give some instruction. Therefore, the results in terms of pleasure has varied greatly. And one forgets the impending O when a provider inadvertently jabs your rectum with her fingernail, or decides I would like my hole f**k very hard with her finger. So I have decided not to ask any more unless I know the woman clearly has had some experience.

I have pleasurable instruments (see reviews)
that are becoming very popular

I am very interested in tantra and want to learn more about the prostate.

I just love making people's toes cur