I can't only speak for myself, anything I've done to grow my nipples specificially has failed to achieve permanent results. For some reason I get amazing huge nipples from lactation pump if I'm lactating and just keep going but its never permanent for some reason. Same goes for supplenips and nipple pumps. I don't understand why this is because I've done extensive hours on it. Only way mine seem to truly grow is more time on HRT and more breast development in general. 

Others seem to be getting permanent results all the time, but I just can't. The method is a sound one, but I guess its a bit of a coin toss how good results you get?