I had an ex that was huge, and although he never fit all the way in, I got used to his girth after about a year of regular sex...the vag is muscle after all and will stretch and tighten with stretching and tightening activity; some people just have a more flexible vag lol

with large clients I would usually say we can only do it with me on top and they won't go in all the way, then I can control it, or only insert the tip and use a lubed hand to cover more of him. When I first started I was used to large penises after my ex but not anymore, as the vag will tighten back over time with inactivity or natural muscle toning.

another good position was me standing up and him behind, I wouldn't arch my back or anything so he can't go all the way in or at that super uncomfortable cervix-hitting angle. If you know a large repeat client is coming, it may help to use a vibrator for a few minutes before the booking to get as much natural lubrication and vag muscle relaxation as possible. I found "bearing down" as you do at a dr. apt before they insert can help to get the first part of it in with less pain

I had a client recently who was absolutely enormous in both length and girth. He came on the first day of a tour I was doing and I knew if I had sex with him that I would probably not be able to continue on with the tour. I told him that if he wanted to stay he could have oral and hand relief but I couldn't have sex with him because he was too big and I'm small and tight. He was fine about it so it depends what the client wants. I know if he had wanted sex I would have just given the money back and apologised. It's not worth it to me to be in pain and then potentially be unable to work.