>>28215
Do not follow this advice without doing serious research on harm prevention/risk minimisation.
See https://youtu.be/8Xq8CMGY8_4?t=629 or https://www.reddit.com/r/Drugs/comments/4t59la/read_this_if_youre_thinking_of_taking_dxm/ for an example of one obvious thing that can go wrong.
https://www.reddit.com/r/Drugs/comments/3pwfhd/please_dont_recommend_more_than_a_1st_plateau/ talks about enzyme deficiency.
I'm not educated on DXM, but I found https://www.reddit.com/r/dxm/comments/2nsdrl/the_complete_guide_to_using_dxm/ whilst googling.
Drugs are complicated and there's usually a lot of ways to fuck yourself over. Make sure you check out harm prevention channels on youtube and read information on places like tripsit.me or erowid. Less applicable for DXM if you're getting it via medicine but make sure you reagent test any drugs you buy from someone before taking them; testing kits are readily available and not that expensive.
Make sure you use a pair of scales to dose if the drug demands it. For stuff where the active dose is below 20mg, you need to look into volumetric measuring, where you mix a larger amount of the drug into some other inert substance evenly and then measure out a larger quantity of that. Never eyeball doses.
Don't be relaxed about taking drugs you aren't 100% sure you understand.