Dude, this it's pretty coincidental you all this question. I'm paranoid and my mind first tells me that I'm being monitored'.....check this out, a friend of mine spent hours searching just yesterday for hours, in his own little meth induced devotion to find the answer. He was amazed that the entire internet did not have a single piece of information regarding your exact question.
He is on 24mg of did per day and he never did METH before but had smoke crack for the first, while he was on subs,he never got that euphoric first hit. He was pretty sure it was the subs also blocking the crack. Now last night he was shooting METH and smoking it.
He thought he should have been more euphoric and overall much more horny.