In the case of morphine, especially if you're not down for IVing, plugging is certainly the way to go. Snorting it is okay, but the drip is completely dreadful. Plus plugging has the whole higher bio-availability thing going for it, too.
i think however the natural limit to redosing plays a part in it for me. I am unlikely to go through the trouble and awkwardness of multiple plugs, one in a day at most. The only problem I have ever had is "leakage", sometimes I fail to get the liquid deep enough and I drip - I am hardly about to recover that drip and ingest it in any other way. It is as good a rush as any I've ever had from snorting. Now beyond that, if you are working with a defeated time release matrix, it is far more pleasant to have that sticky guck in your colon than it is to have it persist in your nasal passages and that resulting crust in your nose.
Too bad plugging is not any more efficient with opana as it is with eating it as the Timerx matrix is a bitch and currently the only opiate I am willing to use is the spare opana I was given recently.
to the OP - if you want to get a glimpse of what IV is like without breaking your skin, violating your bodily integrity and dealing your pride a blow with a needle, try plugging - it isn't that nasty, it is self limiting and it is quite thrifty for certain drugs. It isn't that same knock down rush but nothing can be and I drew my line at IV when I started shooting cocaine. it was far far too good and far far too short, I couldn't see myself breaking my skin every 35 minutes even if it was a nice rush so I vowed never to do it again - that was 35 years ago. Of course shooting LSD sealed the deal for me.