1. To fuck or have sex.
"
WHAT THE FUCK ARE YOU DOING WITH MY GF!?"
"I'm just pushing in my balls. It may anger you, but I like fucking people."
2. To play with your fun parts.
"
What the hell is going on here?"
"It's just me pushing in my balls. Y'know, playing with my fun parts?"
3. To load a Nerf RIVAL blaster.
"Crud, I've ran out of ammo! I need to push in my balls!"
"Push in your balls?
What do you mean? Is this some innuendo?"
"No, I just need to reload my Nerf RIVAL blaster."