To exert a large amount of force or pressure to a male's testicles or general genital area.
You've been TESTEfied.
Shut up, or I'll testefy you.
Kid 1: You're a jerk!
Kid 2: You have no balls *kicks kid 1 in groin*
Kid 3: You've been testefied by Kid 2!
Another meaning for testefy:
To defile a target object or person using your scrotum sack, causing them to be immobilized with fear, giving you an unfair advantage over the victim.
Hey Jack, I should wake up George and testefy him.
That kids balls hang so low he testefies the grass when he walks.
Breaking news: Man dies from testefication.
The local testemorph testefied his dog and it died.