Uncontrolled Substance is the fourth mission in The First Dose series from GTA Online's Los Santos Drug Wars update.
This mission is more of an experience than an actual mission. All you have to do is sit through a casual trip that your character will go through.
You still need to control your character, but it is a linear path, and you must follow whatever Dax asks of you during the mission.
Once you've come down from your trip, it's time to get back to business in the next mission: Make War not Love.
