One handed flutterbies arent as hard as youd think, the two hardest things I found in getting them were the passing from hand to another and keeping the planes of the swing reasonably flat once Id done the pass. Do the pass in two stages, first let the poi slip from your two middle fingers (if using double finger loops) to between your finger and thumb. This is most easily achieved on an upbeat with the starting point at the very end of the downbeat. Then experiment for a few beats till they poi begin behaving a bit wildly and pass back to your other hands finger and thumb, gain control again then repeat the process. Easier with single finger loops.