What causes molecules to stick together in liquid water

This sticking together of like substances is called cohesion. Depending on how attracted molecules of the same substance are to one another, the substance will be more or less cohesive. Hydrogen bonds cause water to be exceptionally attracted to each other. Therefore, water is very cohesive.

When molecules stick together in liquid water it is because the atoms are beginning to slw down and stop so then the moleclues start to stick together in the liquid water causing the moleclues to create a sticky texture.