When you look at the Shadow Hand, a skeletal array of metal limb and muscle, it may not immediately bring to mind the subject of sex. But the robotic hand can touch, sense, move and grip almost as well as a human hand might. It can detect force, micro-vibrations and variations in temperature. Encased in its bundles of sensors and circuits is all of the delicacy and precision of human touch. It’s the kind of invention that could make sex with robots feel like the real deal one day.

What gives the Shadow Dexterous Hand its tactile abilities is haptics, which allows a piece of technology to communicate through touch. The Force Touch feature on your iPhone? That’s haptics at work. The way your phone vibrates when you catch a Pokémon in Pokémon Go? That’s haptic, too. These things may already turn you on. But trust us, that’s only just the beginning. Haptics are what will power the coming sex machine revolution.

Already there’s lots of kinky stuff on the market that relies on tactile technology to make sex more stimulating. The Vibease, for example, is a vibrator that vibrates in sync with the climactic moments of an erotic audiobook. Companies like OhMiBod and LoveSense make teledilonic sex toys that allow partners to stimulate each other from far away. Last year, Lovense partnered with porn producer VirtualRealPorn to integrate its Bluetooth-enabled sex toys into VR porn.

“The basic idea is to allow the brain to be tricked into thinking the experience is real,” Eddy Olivares, Lovense’s marketing manager, told Mashable at the time.

The future of haptics, though, means virtual sex that’s far more realistic. And it won’t require a human to operate the remote.

In April, a viral video circulated of “full body virtual interface”—a haptic sex suit complete with crude silicon boobs to give a user the full experience of sexual pleasure while immersed in VR. Though many outlets reported that the suit was a real prototype designed by Japanese sex toy company Tenga, it was actually an April Fool’s hoax by another company, Japanese developer Illusion. Prank or not, the Illusion VR suit is not all that far from where sex toy manufacturers are betting that sex will go.

In 2013, Illusion unveiled a cobbled-together contraption that allows users to participate in a simulation in which they receive sexual favors from an anime character in VR. The company took a haptic device originally designed create vibrations from gunfire in first-person shooter games, and repurposed it so that it holds a Tenga sex-tube instead of a gun. When someone wearing an Oculus Rift watches the simulation, the device makes the sex-tube thrust at the appropriate moments. (Tenga gave Illusion permission to use their device, but contrary to other news articles, didn’t actually help them develop the product.)

Illusion’s sex-simulation game isn’t available on the market, but it’s clear that’s the direction the company sees itself headed.

“I think in the future, the virtual real will become more real than actual real sex,” Illusion developer Naoyuki Ootsuru told Motherboard* in 2014.

Lovense, too, has been working on creating sex toys to make its VR porn experience even more realistic, using magnetic technology to create male sex toys that move themselves in sync with a video and toys for women that mimic thrusting. For now, when users pair a Lovense sex toy with compatible videos, the device will vibrate or contract in sync with the porn actor’s speed. But eventually, the idea is to create a more immersive experience with toys that move themselves.

Olivares told me that at this point the “bones” of the new toys are “essentially done.” Development of the “brains”—testing different sensors to see which syncs with the VR videos best—is expected to be done in another four to six months.

You can see a prototype of the male toy here, via the company’s Instagram account:

The biggest advancements in haptics, though, are likely to come from outside of the adult industry. The Shadow Hand, for example, uses some of the most sophisticated haptic technology available, allowing a hand to not just move like a human hand but to sense temperature and the force of touch. The Shadow Hand, the flagship product of U.K.-based Shadow Robot Company, wasn’t designed with any specific industry in mind; founder Rich Walker just wanted to give robots better hands. Allowing a robot to feel what it touches has uses in all kinds of industries—think bomb-disabling bots that can feel the textures of wire in their hands, and surgical bots that can not just see but feel a person’s insides.

For now haptic sex toys rely mainly on movement—mimicking the vibrating, thrusting and convulsing of sex. But haptic technology is already much more advanced. Companies like SynTouch (which the Shadow Hand uses) allow machines to feel texture as humans do. Ultrahaptics uses ultrasound emitters to allow users to ‘feel’ virtual worlds. It won’t be long before haptic sex toys incorporate these advances to mimic other sensory aspects of sex, like temperature, to make sex seem all the more tangible.

Right now, the biggest technological hurdle to achieving virtual sex that seems real is creating tactile feedback that can travel two ways, the way it does between two real life humans. For now technology only allows such information to move either from machine to human, or human to machine.

“Today, if I put one of our hands on a robot, I can make the robot copy my hand,” said Walker. “But there’s a gap on the other side of system.”

That, he said, plus most haptic feedback devices are “horrible clunky machines.”

“How do you get sensations that are human compatible and good enough that we read them as real?” he said. “Right now, if we want to give people a sensation that’s similar to touching something like skin or fur, we can’t.”

Walker said that right now, the main thing preventing such advances is a lack of market demand and the cost of prototyping. He said the industry needs the a kind of ground-breaking innovation that does what accelerometers did for VR—making it so cheap to develop that anyone can get in on the game.

Already a handful of companies on the forefront of virtual sex have collapsed, struggling to find investors or a big enough market. RealTouch, a “digital brothel” that allowed paying customers to use teledildonics to have sex online, faltered amid patent licensing issues. A haptics-based sex social network called FriXion seems to have simply disappeared.

Olivares said without more competitors in the sex tech market, innovation is likely to be slow.

“I don’t think we’ll see full-blown body suits any time soon,” said Olivares. “The amount of development work and money required for that is too much of a risk. No one knows if consumers will be open to this type of experience (and are willing to pay)!”

Walker, though, is more optimistic. He thinks we’re only a few years away from the kind of breakthrough that will make full-blown haptic suits a reality.

In just a few years, he imagines, traveling parents will strap into their haptic suit to give their kids a hug goodnight via Skype. And like all great advances in technology, after that it won’t be long until we’re using it for sex.

*Correction: This story originally cited a Motherboard story that portrayed the Illusion VR sex simulation as a Tenga project and attributed this quote to a Tenga CEO. However a Tenga spokesperson told Fusion that the Motherboard story portrayed many misunderstandings. The sex simulation, he said, was an Illusion project in which Tenga had a limited partnership. And the quote featured in this story was actually said by Illusion’s developer, as translated by the company’s U.S. sales manager Tsuneki Sato (who is not the company’s CEO). The story has been updated to reflect these facts.