Do you know any stories/books that fit these criteria?

My ideal book involves a straight man surrendering with dignity to pain and/or sexual humiliation.  Here are other attributes:

There is no personal relationship between the tormenter and the victim. The MC doesn't want to please anyone.

The action takes place in the real world. Make believe historical OK, but no sci-fi or fantasy. 

I got involved in erotica at the beginning of 2021 (after an initial spell in the '60s and '70s). I've been looking for such books and have really only found two by Billierosie, The Enslavement of Eli and The Rebellious Slave.

I've written my own four stories along these lines, one about to be published, I hope, and one available only on Smashwords for non-con reasons. https://www.smashwords.com/books/view/1088381 (FREE) Check my profile for the others.

Anyway, back to my request. I'd be really grateful if anyone knew of other such stories.

Well, it so happens that one of my stories follows this pattern. Basically, the mc submits to an initiation caning in order to infiltrate a cult to help avenge his wronged daughter. It's called "Paco's Tale: The Initiation Caning". It's in my series, "The incredible sexual summer of the Lopez family". You might find it meets your criteria!

Quote by AG31

My ideal book involves a straight man surrendering with dignity to pain and/or sexual humiliation.  Here are other attributes:

There is no personal relationship between the tormenter and the victim. The MC doesn't want to please anyone.

The action takes place in the real world. Make believe historical OK, but no sci-fi or fantasy. 

I got involved in erotica at the beginning of 2021 (after an initial spell in the '60s and '70s). I've been looking for such books and have really only found two by Billierosie, The Enslavement of Eli and The Rebellious Slave.

I've written my own four stories along these lines, one about to be published, I hope, and one available only on Smashwords for non-con reasons. https://www.smashwords.com/books/view/1088381 (FREE) Check my profile for the others.

Anyway, back to my request. I'd be really grateful if anyone knew of other such stories.

Natural Law by Joey W. Hill may fit your request. I listened to the audiobook a few years back.