I have seen some discussion on the forum lately and wanted to share my experience with this. I find SL/PE1 and RC/PE6 to be the most grueling. The hollow hold variations could pose a challenge as well.
I use the principle of dissociation. Instead of feeling my body from a 1st person (associated) point of view, I "watch" myself from the 3rd person (dissociated).
The ways that work for me are specific to my gym and its setup. I do SL/PE1 near a mirror to make sure my arch is tight and my legs are perfectly straight. Then I close my eyes and continue to picture myself in the mirror. If I feel myself getting tired, I first make the imagined version of myself tighten up his arch up.
I perform RC/PE6 on one of the parallel bars. Because the high bar in my gym is visible from there, I usually do this one with open eyes. I just pretend I am doing the hold up on the high bar, and I watch myself from afar. If I feel my grip loosening or my elbows straightening, I watch the image of myself fix his form and hold it stronger up on that high bar
This takes all of the focus off the discomfort that I think I'm feeling in my own body. The more I focus on making these perfect form pictures in my mind, the more the time just flies by! Interestingly, I don't do this for planche work. There is too much going on in the holds (protraction, depression, widening, hollowing, etc.), where I need to remain fully associated in order to focus on squeezing the right muscles in the right way.
I'd love to get everyone's take on this. What works for you? What doesn't? What modifications do you make that are specific to your own setup or your own abilities?