squeeze off?

At first I felt a bit afraid of being alone with Dad. His breathing pattern started sounding finite. Each inhale was a jarring gasp that seemed to come in 10-minute increments. When he exhaled, it sounded like a January wind whistling through a small crack in a window. I learned later that is what is fondly referred to in hospice circles as a "death rattle."
I climbed into bed with him and grabbed his hand. I put my lips right up to his ear, and spoke to him in my normal voice.
"Dad, squeeze my hand so I know you can hear me." He squeezed back. I wanted him to squeeze it off.

What does "squeeze it off" here mean? Thanks!