I don't do foleys on males (I work in L&D) but from what I remember in school, you advance all the way for males because their urethra is so long. As for females, you are suppose to advance another inch or so after seeing urine return. I personally just advance it all the way, inflate the balloon and the '"excess" just slides out anyway. It's an outdated practice to pull or tug on the catheter.
The only time I've had a foley I was numb and didn't feel a thing but I have had pts who say it is uncomfortable even when properly placed. But it should not be painful.