Any workarounds for the slippery back?

[HeartBle33d]

As manu of you have experienced, the z3 series features the most slippery back that human kind has ever made. I have been wondering if there exist one way to make the back of the phone less slippery. Sure, a case always helps but I really enjoy how beautiful the phone looks completely naked.

[Thommo]

Some use bumper cased which only go around the edges leaving the front and back clear, I've also seen some who have used a felt type material stuck on in areas where they would mostly hold it