If your not sure how to do it you can cause them harm just as you can with probbing. You pull gently down with your thumb matched to the top of the vent and roll your other thumb from tail toward vent while slightly bending the tail. If you have a local reptile person who is familiar with it they may be more than willing to do it for you.
Well ive seen people do it and ive read up on how to do it. It seems easy enough. I wouldnt trust my LPS with it.