Maybe that's my problem. The cable I'm using doesn't really seem to have any memory. It just flubs around. If I twist it gently or tightly it just flops untwisted... So the only way to keep it twisted is by the wire's memory? There's no other technique to somehow keep them twisted permanently? Because even twists from memory of the cable would come untwisted it you spun them with your hand, right? I don't want that.
It confuses me that if you got both ends tied/soldered/heatshrinked how could it untwist?
ultimate solution: heatshrink the whole wire.