Whenever my doctors office says this to me and I asked her what they mean she said the pain of getting the needles inserted didn't seem to bother me. Kind of like when you experience a problem and you just bounce back you're said to have tough skin everything you experience just bounces off. instead of tearing into you.I can sit there and not have any reaction to pain where as alot of people experience anxiety before getting needles and during it squeeze the eyes shut and look away and so on. me I can sit there and watch from my tunnel area as the needles press against my skin and then go it, draw the bloodwork needed and then watch the taking the needle out with no emotional pain, panic and no physical reactions.