Long-distance relationships can be difficult and, while apps like FaceTime, Snapchat and Skype mean lovers can see and talk to each other - what about real physical intimacy? Enter: the Kissenger.

A gadget that enables couples to kiss each other through the internet, the Kissenger - derived from the words kiss and messenger - has been the subject of university lab tests for the last couple of years.

So how does it work?

Essentially, it’s a brightly-coloured holster that attaches to your smartphone with an inviting plastic pad attached at the bottom.

When you lock lips with it, the pad senses pressure points and transmits the sensation through to an identical holster on your partner’s phone, wherever they may be.

“Kissing is the most direct and universal expression of intimacy and affection,” Emma Yann Zhang, who worked on the prototype, told an audience at the Love and Sex with Robots congress at Goldsmiths, University of London.

“It's a way for us to bond and maintain intimacy in our relationships.”

The creators of the device say it has also helped users get on-board with machine-based touching and while it is aimed at couples, it can be used outside of romantic relationships. “Parents can also use Kissenger to give their children a kiss on the cheek when they are away at work,” its creators said.

​While they admit that a lot more work is needed to create a more lifelike make out experience the next stages of development are already underway.