If you're plugging and you are a first time or very in-experienced Opiate user, I would suggest plugging only 15mg to start off with. Plugging, after I.V. administration is the most effective route to go. Although I have never had the guts to plug anything, I am aware that it does not get metabolized by the liver this way and there is very little loss. So expect it to be very overwhelming.
I only took half a "green meanie" once when I wasn't very knowledgable of mscontin, didn't even bother scrubbing off the waxy coating/time release, so the effects weren't at all what you would call intense by any means, considering I took them orally.
Although, I was very heavily sedated and couch locked for half a day.
I would love to get my tight little mittens on some mscontin these days though...