Apparatus and methods for applying liquid onto a substrate include a nozzle configured to be connected to a liquid source. The nozzle further includes a distribution passage with a length that can receive the liquid. A piston is positioned in the distribution passage and a slit-shaped nozzle opening is in fluid communication with the distribution passage. The piston is movable in the distribution passage so as to vary the length that can receive the liquid. The nozzle opening communicates with the distribution passage via a plurality of spaced apart outlet channels having respective outlet ends. The outlet channels are formed between first and second nozzle pieces each having a tip portion at the outlet ends. At least one of the first or second nozzle pieces is flexible at the tip such that the outlet ends open when under positive fluid pressure and close when the fluid pressure is reduced. An application valve is coupled to the nozzle for selectively interrupting or enabling a flow of liquid to the distribution passage.