Well, if you think of all this was difficult, I assure you this will be even more difficult.
Search a video that make you REALLY HARD, about 10 minutes.
Then open this link:
http://bestdrumtrainer.com/st/#60_240_A_NTS_600_60_64_20_O
Once you have loaded , put both play and have fun with the metronome .
If you edge, you must HOLD IT to the end of the video.
If you go over the edge, ruin it and collect all your cum with your glass and finish watching the video without touching .