Sight: You close your eyes. You still “SEE” (try it sometime) but most external influence is blocked by a thin layer of skin, pulled in place by the muscles of your body, at your own conscious will.
Smell: You pinch your nostrils shut. Your smell receptors are still working, but no new smells can enter. You do this with the muscles of your body (fingers) at your own conscious will.
Hearing: You put your fingers in your ears. This blocks most external noise, but your ‘ears’ are still working.
Taste: You close your mouth tightly, so nothing can get inside. The tongue is still there, but no external stimulii enters.
Touch: Ok. Beats me. This is a tough one. Can you count ‘just standing in once place without touching anything’ as ‘turning it off’? I dunno. I do know that I and a few other people I’ve met have some conscious control over it, in that we can ‘will off’ our tickle response. If I don’t want to feel someone tickling me, i just decide it doesn’t tickle. I still feel the touch, however, but it doesn’t make me laugh.
Ejaculation: Well… TMI maybe, but there’s something called ‘tantric sex’. I don’t claim to be an expert in it by any means, but there is a way to use the fingers to block the Vas Deferens (Sp?) during orgasm, which diverts semen into the bladder. It also feels REALLY good. q;}