Natural lowlights?? question!

Sure its possible.  Just pin up the pieces you want to leave lighter, pinning them on top of your head should keep them out of the way, then just dye below them so the dye won't drip on them.  The sides may be more complicated, because you may put some dye above them that can drip.  I don't know if foils would really keep dye that is above them from dripping on them, it might help.  It depends how blended you want them to be how complicated it will be to do.  Just think about it and make a plan for pinning it up before you start doing it.