hmm have you ever tried a menstrual cup? it would be interesting to see if it catches anything, so maybe you could tell if its coming from the vaginal walls or deeper in. to me it kind of sounds like excessive vaginal wetness, like maybe theres a nerve issue causing the aroused wetness response at random times. you mentioned you have some spinal damage which could be related. somewhere deep in the memory banks i seem to remember people getting weird genital symptoms from lower spine injuries, but i could be misremembering.