No onscreen prompt after taking the "Intimidation" perk

Since the game doesn't tell you how it's supposed to work, I didn't realize for weeks that there was even was a prompt.

I thought that somehow it was automatic (how was I supposed to know any different?), and somehow I was doing something wrong. Was I not close enough? Was the sweet spot on the NPC really small? Do you have to aim it at their right testicle for it to work? Did no one take me seriously since I was wearing Silver Shroud armor?

Did Bethesda just fuck up again?

I'm on PC, using an Xbox 360 controller and I don't have any mods that change npc behavior or UI.