push up on (something)
To shove, thrust, or press something from below in order to force it upward. A noun or pronoun can be used between "push" and "down." Push up on this hatch so I can access the control panel. She pushed up on my feet so I could get over the top of the wall.
push up on something
to raise something upward; to push something up from below. Larry pushed upon the trapdoor and lifted it so he could climb out. Push up on this lever if you want the lights to get brighter.