Like Libraries, I had an excruciatingly painful and long back to back labour.
First 8 hours or so in water pool with no pain relief, then had gas and air which helped somewhat. In the same way a plaster might help if you'd amputated a leg.
Over the next 24 hours I had diamorphine (didn't touch the sides) and an epidural, which absolutely saved me. Mind you, it was necessary to get me through the myriad of surgical interventions which followed. So wasn't exactly an optional thing.
My long and detailed no-pain-relief birth plan was effectively abandoned. As was my hypnobirthing practise. The stuff about a high pain threshold is bollocks. I have been through a lot in my time and always coped fine. But this back to back labour was like someone was breaking my spine from the inside. You can't plan for that, you get through it as best you can.
In the same situation I'd have diamorphine again. While it didn't tackle the pain, it was a brief distraction from it and gave a warm fuzzy feeling which, after so long in screaming agony, was rather nice.
Seriously thinking of an ELCS for my second - which is rather a change from the hypnobirthing and yoga plan I had for DS.