Question: Anal Ecstasy

This is kinda weird for this site but folks here have been very kind and have shown themselves to be experienced in a wide range of pleasure. Do let me know who else I can ask.

I (56M) developed a yeast infection because of the way a diabetes drug works. I have had ones before around my glans (I am uncut) and around the exterior anal area. The areas itch until the antifungal meds kick in.

This time the itch was just inside the sphincter. Scratching that itch is orgasm level ecstasy. My cock remains flaccid and I do not ejaculate, yet it's very strong and leaves me breathless and euphoric. To be clear, it's not a quick itch. It takes about 2 minutes to get there but then it just keeps going as long as I am rubbing the areas. The only reasons I stop is that I don't want to draw blood and because the pleasures become uncontrollably strong.

Has anyone else experienced this? More crucial, how can I stimulate/simulate that without the itch? I would think both men and women could experience this. If this is tantric in nature, I would love more information.