To tap off it simply remove some of the insulation off the wire that goes to the cigarette lighter. Make sure you know which is positive and which is ground. If youre not sure use a multimeter. Simply wrap your wire (nice and tight, couple of turns at least) to the existing wire with the insulation removed. To stop it shorting out wrap it up with electrical tape. If you have a soldering iron and solder you can solder it, if you have heatshrink you can cover it with heat shrink or you could use crimps. If you dont have this gear though the wrapping of the wires covered with electrical tape will do the job. Just make sure the tape covers the wires completely, maybe do two or more layers to be sure. If not it could short out and blow the fuse.
From there you run your wire to where you want the neon to be. This may mean you will need to pull the dash apart a little or you may be able to run it through without pulling anything out. If you are after more help removing panels to run your wire youre best off searching around or asking in the VY section to talk to the guys that have a VY and have probably done it before.