Remaining Soft and Reaching Impotence

I was curious if anyone could suggest ways to remain soft and/or reach a state of impotence without relying too heavily on medication? I considered that perhaps a numbing cream might do the trick. Does anyone have any experience with using one? It may seem odd, but my goal is permanent impotence. After learning that some men in chastity eventually stay soft while wearing their devices, I wondered if that path could be mine as well. See you later and hope to get your thoughts soon ^.^