He is probably talking about methadone.
Old post, but I will reply for others.
You have to be in deep enough withdrawal to start. You can go from 200mg to bupe. But you would probably need to skip around 6/7 days. I know people that have done it from ~100mg and I did it from 65. We all went into post acute. Most likely is gong to happen regardless if you are long term doser.
In any case, start with the smallest piece of bupe. Wait an hour. Another small piece. Wait an hour. Will probably take a good 24/36 hours to induce, but you should be feeling fine within 48 hours. How long it took me. Most important part is to start with around .5mg of bupe and wait that hour. If you are getting worse, then wait maybe 2-3 hours before another .5mg. Last thing you want to do is stick 6mg of bupe at once. .5mg of bupe won't put you into horrible post withdrawal if you waited a good 6/7 days.
If you can make it 9/10 days even better.