First off u don't "trip" off opiates. That would be the term for being high on psychedelics like LSD, shrooms, peyote, DMT, etc.
If u take the pill by mouth you don't get a rush, especially with oxycontin(the extended release form of oxycodone). If u have oxycontin u can crush it and wrap the powder in tissue paper and swallow it, snort it, inject it(not for beginners like u), or plug it(up the ass. dissolve it in 1ml of warm water than suck it up with a oral syringe. probably seems weird to u but it's the best way of doing it). If u have the "OP" kind u can't crush it. You'll have to take twice the dose and it'll last twice as long.
DON'T snort percocets. The kind with Tylenol in them (acetaminophine, paracetamol)
Start off with 10-20mg. Opioids like oxycodone r milder than weed but feel nicer. After about 30min you'll start to feel warm and fuzzy, relaxed, sedated, dreamy, have extremely positive mood, have no anxiety and itchy. Your pupils will be a lot smaller. The experience lasts about 3-6hrs with an after glow for new users.