I (F47) tried it with my guy (M51), both our first time, last week.
(We are in a renewed relationship, if that matters, so known each other ages, but only recently back as a couple. New start, new things!).
It was at my initiation, initially. We were both initially VERY anti. But during oral/PIV, I gently touched him there first (yes, I asked first), just fingers, and we were both intrigued, and he really liked it. He then touched me, manually, and I loved it too. We talked at length about trying AS, decided we'd try, very slowly, very gently. I was incredibly turned on by this stage, and very much ready/in the mood.
It was insanely amazing. He was only maybe a quarter in, but he said it was incredible for him. He came, and declared it out of this world phenomenal. Most intense orgasm he'd ever had.
I had some sort of 'thing' – not quite sure it was an orgasm, it wasn't the same as PIV/oral orgasms, but I had some sort of intense mind-blowing sensation. It was fantastic, and I felt fulfilled.
We tried again the next day but I was a little less ready, and it didn't work/he couldn't maintain it, so we let it go that time.
I can't imagine doing it regularly, as I have concerns about it damaging me, but, if he stays at only a quarter in, and is as gentle as he was, I'd like to repeat it as a special thing, maybe every few weeks. Maybe we'd progress to deeper, but there didn't feel much need.
Can't believe we did it, really, but also now can't believe we only tried it now.