To make it right you need to use less flour and more "творог". And don't mess up tvorog with cottage cheese or some other western substitute. Buy it fresh in a good supermarket or farmers market, or do it your self. You can find some recipes here: co.uk
Two other hints: 1) if the dough is too loose, pop it in the freezer for a half hour or so; 2) make them every week so that you get the feel for it. It takes several attempts before you know when the dough is the right consistency.