My yoyo just won't sleep!!!!?

I have a duncan butterfly but no matter how many videos I have seen on youtube and tried out their instructions I just can't do it. And don't tell me it won't sleep because it doesn't have those capabilities, because I have made it sleep by accident so it can sleep, but I can't make it sleep when I want it to. Any vids or instructions would help. If you need anythin else to help you I will provide.