I've only done two different "illegal" drugs. (legal drugs include medication) The drugs I have taken are DXM (in cough syrup) and good old weed.
DXM is definitely an interesting drug. You can have a different trip every time you take it. (Pretty much like other drugs) I haven't take SUPERMASSIVE amounts of it, but enough to have good trips. I remember coming up; I start seeing spots in the sky that kind of look like tiny oil leaks. Then I get a buzz and slightly dizzy, kind of like alcohol.
...I'm going to skip the pointless inbetween details...
As far as I've gotten with the drug I've experienced intense feelings of disassociation from my body and euphoria, as if I had not a single worry in the world. Everything seemed right and I felt as if nothing could hurt me.
As far as the dissacoiation went, I felt almost completely out of my body...but in control. Kind of like a driver driving their car along. (not exactly..but I couldn't think of a better description) I would look at my reflection in a mirror or window and think to myself, "What is that in the mirror? That can't be me. No.". I looked like an alien. (yeah..)
I'll also add that it can make people think alot. About life, and about anything, really.
The come-down is really slow for me and sometimes I think to myself that I won't come down 100% and then almost panic.
Again, I think it is a very interesting drug and you should read up before doing any kind of drug. Don't jump into it, there isn't any hurry.
I don't know if the above will make any sense to you, so I apologize if it didn't help. (I'm bad at describing and elaborating on things)
ehhhhhh
EDIT: Every time I have taken the DXM, I have always drank the syrup with guiafenesin in it. I have NEVER gotten sick from it. It will sit in my stomache for 20 minutes and feel a little strange, but it is nothing terrible for me. I guess I'm lucky.