Just found some a very helpful video for silk painting? Jacquard Resistad is the most popular water based resist. After applying it to silk, it must be heat activated through ironing or steaming before dye is applied to activate its property of holding a line.

To add the mixed Resistad to the applicator bottle, I have a little funnel that works great. After the Resistad is in the funnel, a squeeze on the applicator bottle creates a small suction and sucks it into the bottle.