I took DXM for the first time last weekend. I first took about 150 mg, then another 300 mg 1-2 hours later, so 450 mg in total.
I remember Not feeling anything for hours. Then, sudenly, I realized I had been tripping for quite some time and the "fun" started:
Me and my mates L and I (L was also on dxm, same dosage..I was only on speed) decided to go to the park. I was feeling very drunk at this point with a slight psychedelic edge. I had a growing feeling of dissocation and was actually quite enjoying myself. However, as the effects were getting stronger, my head first started to glow and got very warm. This later dissappeared, making way for some extreme nausea.
At the peak of the experience I was completely out of it, and I remember one of my mates asking me if he should call an ambulance. Luckily, I managed to show my mate L a big grin, and he got the message: I was doing fine. At this point I was crawling through my own vomit, and the effects were very intense, though extremely physical. My visual input became very distorted, everything looked very chaotic and I couldnt make out any clear forms anymore. My mind was completely occupied with trying to cope with the extreme strokes of nausea that were overwhelming me every ten minutes or so. As I was lying next to a tree, trying to stay clear of my vomit (which, as I saw the next day, I didnt succeed at), I got some nice visuals on the tree. The tree seemed to be made out of ropes, a very mushroom-like hallucination. This would be the only real psychedelic effect I got that night and the rest of the night could be described as drinking a bottle of scotch when yer already too drunk to stand up straight: very intense, but very physical. Way too distorted and chaotic to make antyhing out of it. Although all this may seem pretty unpleasnt, I actually enjoyed the sheer intensity of the experience. It was just too chaotic and much too physical to be really worth the horrid nausea.
I really don't feel I now know what DXM's all about, so I'll guess I'll have another go at it sometime in the future. I'll probably dose a bit lower, somewhere around 300 mg.
After the experience, I dropped some speed and the come-down was very smooth. I felt like a million bucks the day after.