There are several methods for filling lip gloss tubes. They are intended to be machine filled in a lab, but you can easily fill them at home. There are commercial grade syringes that work well for filling them. We have also seen some small business owners use household tools such as a turkey baster, or pastry icing applicator. These methods are elected in place of the preferred method where tubes are filled in a cosmetic laboratory by machine. It also comes down to what would work best with the viscosity of your unique formula.