I have a fair bit of experience, I can't say for certain but about a hundred or so partners over the years. I could always tell the ladies who use vibrators a lot, because you cannot make them come with conventional means! My theory is the clitoris gets desensitised with regular vibrator usage, and oral sex just doesn't work after a while. You can help these women to come, but not easily and often you need to move from oral sex to something else.

I find oral intimate and personal, and to think it can be destroyed is sad.