A nanite based interface.

"Hey K-T, come here and remove your clothes. I need to test something." said his sister as soon as he entered the lab. She was wearing some blue jeans, a cream colored turtleneck and a lab coat, some sort of control screen strapped to her left wrist and strange glasses resting on her forehead.

"Are you not even going to tell me why this time?" he retorted, yet still slipped off his t-shirt and dropped down his shorts. His dick was still hard but at least no longer pointing up, helped in that by the chilling temperature of the air conditioned lab.

Emily approached him with something that looked like some sort of gun with a glass vial on top of it. The vial was full of a liquid of a metallic color. The color was one of those unreal ones, outside of the color spectrum typical of these various new elements recently discovered, impossible to describe using the words human had used since they learned to talk.

In quick sequence she put the gun on him and pressed the trigger. One time on the side of his neck, one for each arm, two on the chest, one above his groin and one on each leg. This was one of those modern neddleless injection guns and while doing this she had injected in him what looks like half a can of soda of the special liquid. It was thankfully painless.

"Why bother? You're going to let me do it anyway and you barely understand what I explain." She said. "You are now host to a colony of AI controlled nanites that can interface with my computer. This will in itself be a breakthrough discovery but will also help us in all future testing."

"Cool, but what can they do? do I get superpowers now?"

"Don't be ridiculous. Since you are always so preoccupied with how you look I decided to do something for you. The multiple injections were not actually necessary but they help them spread faster through your system, without it I would have needed to wait hours just to do that!" she said pressing a few buttons on her wrist control panel. And lowered the strange green tinted glasses on her eyes.