how do i get bigger forearms?

I'm still borrowing the one my coworker brought in

Play mallet instruments, especially vibes.

i've never done it, but I see dudes in the gym using a weight plate attached to short wooden dowel with a couple of feet of rope. hold your arms out and rotate the dowel (parallel to ground) to raise and lower the weight.

as suggested, I have made a rubber band ball and squeeze it while at work. not sure it's making any difference but it's either that or my coworkers neck.

breeeeeeathe

Working in a commercial laundry for only two weeks actually made an impression on my forearms! Very tough work.