I think the orgasm thing is more in the realm of IV users. I was, and thankfully so, never an IV kind of guy but trying to think of times I pushed too far. I think either nausea or actual loss of consciousness overrode any euphoria so it is a fine line.
I prefer contentment over happiness as the definition though. It is more like hey, I don't feel bad rather than wow I feel good.
Now please keep in mind I have about 19 years 50 weeks more experience than you. I understand your desires, I cannot fault you for being curious. But this site is also full of people who wish they never felt that first sense of well-being and try to caution new users of all the dangers and experiences they personally suffered. Its hard to stop once you do feel it.