My experience is that some women need very different oral sex techniques; indeed some women are radically different to the majority. I've had some lovers who were very, very sensitive, and needed a very light and fleeting touch or else it was just terrible for them. I've had some lovers who were the opposite, and needed me to really get stuck into it to get any satisfaction. The majority preferred an average sort of touch.
So rather than the prophets of doom, perhaps you are doing it wrong for your current girlfriend compared to previous lovers. The way I did it was read my partners body language, and let her guide me to where she wanted me to go.