well, see, a good dilly IV rush is like a full-body, prolonged orgasm to me - seriously, back when i had a lower tolerance + wasn't on daily methadone, slamming an 8 would have me unable to stand. like i'd seriously have to stay seated for the first minute or two otherwise it'd be like someone was clipping me below the knees from behind. sooo good, beats any other opiate for the initial rush, imo, although the high doesn't really have the 'legs' that morphine or heroin do. so, in the sense that the rush of certain drugs can be similar (even equal) to an orgasm, sure.
but as for doing drugs beating the wonderful, spiritual, romantic experience that making love to a beautiful, horny woman who seems to want nothing more than to devour your cock with her pussy is, well.. nothing beats that, ladies and gentlemen. and this is coming from a long-time opiate addict.