All drug effects upon the libido are completely subjective...
I've had many encounters where having popped a few Norco's indirectly caused some of the most (sexually) fun nights of my life... and then there have been times where the very same amounts would totally kill the libido..or so it seemed.
It boils down to a very complicated combination of psychological standing, biochemistry, and sensitivity to the drug being used.
HAhah I remember this one time - this hottie blonde and I were going at it for what seemed like hours.. and as I turned to look at the clock - it HAD been about an hour - of constantly-changing positions and trying trying trying to get off... but it just wouldn't happen...next thing I know, she jumps off me, and asks, "Am I not attractive to you? Am I not good enough for you or something?!" I could have laughed, but I didn't. I just pointed out to her, that she and I both were on large doses of opiates, and that we could even feel our skin rubbing together was miraculous..."Oh yeah...huhuhuh" she says...
It can be a great time, or a waste of time. I recommend being SOBER FOR YOUR FIRST FUCKING TIME. DO NOT taint your memory of such a wonderful experience with something like Vic's. In fact, just get to business - make it special, of course - and remember that when you two are done, you can get up, grab some Vic's, and eat them then. The afterglow from sex, the oxytocin flooding your brains, plus the hydro acting on your Mu's should provide quite the after-sex relaxation session from heaven.