I would say it is a very warm tingly sensation, like MDMA, sometimes I said I liked it better than sex when I first started. Feels awesome and less complicated. But of course there wasn't the spontaneous orgasm I got MDMA . But it was a prolonged good feeling. Weed and Benzos, its also like that cause you don't give a shit about anything. You just wanna close your eyes and immerse yourself in the feeling until you nod out, kinda like sleep but not really, get lost in the high. And sometimes just land where you land and have no idea how long you have been that way but not really care....
I personally like Tramadol as an opioid, because I like the stimulant effect that I relate to caffeine and meth...
But I would start in easy. Don't go straight to morphine pills or heroin. Likely to make you sick sometimes. I did cause I had no tolerance to that shit yet. Start with Tram, it's not CONSIDERED a narcotic but I get pretty fucked. BUT it can be fail for some people. You don't know if you don't try it. If not, go to something with codeine in it, a medium amount.
If it has APAP in it, then CWE it. And make sure you have like benadryl. That shit gives you bad opiate itches. I personally don't like them...
Hope that helps...