push down on (someone or something)
To shove, thrust, or press someone or something continuously or repeatedly forcibly downward. I keep pushing down on the lid, but it won't stay shut. I could feel someone pushing down on me from above.
push down on something
to press down on something, such as a button, stamp, lever, etc. Push down on this button if you want room service. Don't push down on the door handle too hard. It will break.