Back when I was a younger lad with far less common sense than want to get rekt a buddy and myself split a bottle of Robitussin cough syrup.. High DXM content.
We dubbed it "Robo-Trippin" and never visited it again.. Was a good time minus the ridiculous amount of acetaminophen we ingested.. :D
It is definitely a lot of fun, no doubt about it. But all those extra ingredients like Tylenol or antihistamines that you mentioned are what can really get you.
Its probably a good thing you only did it once too. I don't know why, but the stuff just clicked with me. No drug I've ever taken has made me more compulsive/addicted than DXM.
Different strokes I guess =)
At one point I remember seeing powdered DXM available.. Not a huge fan of the disassociate type substances though.
Oh yea, that stuff's out there and extraction methods too. I just chug bottles these days though. And disassociatives are my absolute favorite. MXE and DXM are above all others to me.