When the whumper ties the whumpee’s hands high above their head so they are all stretched out. And then the whumper can invade their personal space with no obstacles. When the whumper strokes the whumpee’s chin and they can barely move away because they are stuck, so they just grit their teeth and look away. It’s just great.
This! They’re so exposed, and unable to back away. It’s the perfect position to have the whumper threaten them with a knife, put a blade against their throat, or outstretched arm, and start pushing ever so slowly. Or to tilt their chin up with it, and lay a hand heavy against their torso as a constant reminder of how close they are, how they could do just about anything they liked and there would be no defence against it.