I think you have answered your own question (how can I taper?) for yourself a couple of times already on this board. You can't. If you could, you would have done it a long time ago and wouldn't continue to find yourself in this scary place. Believe me, most of us on this board have tried to taper and probably believed we could....but the pull of this disease doesn't allow it.
That's the difference between addicts and those people who really can take pain medication just for pain. That's the difference between tolerance, which anyone will get if they are taking pain medication for an extended period of time, and addiction, which from my experience and education is a chemical, emotional and spiritual disease.
The BEST thing you can do is talk to your doctor. he can develop a plan with you to get you off of the high levels of oxy safely and with help. Frankly, you need someone else to have control of your medication. As addicts, if we have it, we are going to keep taking it even when we know we "should" save some for later!
Also, your doctor needs to be in on the plan so he can help find medication that really does address your plan. There are newer and better and non-narcotic pain killers that are definitely worth a try.
You know what you need to do. You've posted on this board and obviously read others' posts enough to know that there isn't an easy way out or a quick answer anymore.
talk to your doctor. Get involved in meetings or possibly even an in or outpatient rehab center. If you keep holding out, you'll keep repeating the same situation over and over. There is no such thing as will power for an addict...no matter how strong you are or even how determined, will power alone just doesn't do it.
Please let us know what happened at the doctors. Chances are he'll be more understanding than you expected...