Excellent account, it gets to the heart of the physical experience. Add to that the arms stretched wide, the body exposed and stretched. Pain and exposure and intense physicality adding up to an erotic experience all round.
After the first minute had passed it really began to hurt, the ropes would dig into your wrists. In order to relieve the pressure from your wrists you have to press up with your legs. In doing that the wood would press into your feet making standing almost as unbearable as hanging."
Now imagine this but with nails added. The discomfort of rope pressing against wrists and feet becomes the sheer agony of iron tearing flesh, rubbing sinew, grinding against bone. Fiery agony with every movement. Is there still room for feeling arousal? Or does pain drive out all other thoughts?