I know you were asking about drugs to achieve this. However, I've achieved this in the past without drugs.
Basically, you want to "get in touch" deeply with your sleep state. Your goal is to bring your conscious mind into your dream state. And you also want to begin recalling your dream states better in your Conscious mind.
You can begin this by doing a couple of things, regularly.
First, you will want to keep a Dream Log or Journal. The reason for this, is it will enable you to begin to have better recall of your dreams eventually. Just dedicate a notebook to writing down your dreams upon waking. If you're really intent in doing this, writing them down IMMEDIATELY upon waking is the best. Not only when you wake up in the morning for good, but if you wake during the night. Immediately write it down. And, a really good tip: SKIP LINES as you write. The reason for this, is that (especially at first) you will forget a detail, and need to go back and add it in. If you skip lines, you have space to insert these afterthoughts.
What should you write down? Well obviously the dream...but ANYTHING that stands out to you especially, even of you don't know why it does. I'm talking numbers, colors, a mood or feeling in the dream, that thing you noticed that didn't quite make sense, etc. (This is also useful for learning to interpret your dreams,,which is something else you may be interested in). Note how you felt. Don't just say,"It was raining and I was soaking wet"...add in things like,"...and I remember feeling really refreshed/alone/cold/the warm rain/it made me laugh..." etc.
After you have done this nightly for a while, you'll begin having far better dream recall than you do now.
The other thing to do - and keep at it, as it may take a while to have success - is to have a little "talk" with yourself before laying down to sleep. Out loud, in your head silently...whatever works for you. Write it down.if that feels right. Tell yourself things along the lines of,"Ok...I'm about to lay down.to sleep. Tonight, I will dream about xyz. I will have complete awareness as I dream, that I am in fact dreaming. I will remember my dream with clarity and detail upon awakening." Etc. Over time, add in more, like,"...and when xyz happens, I will (whatever you want to do in your dream. Example: when it rains on me, I will gather the water in my cupped hands...)".
Your goal is to get the conscious and dreaming brain to recognize one another.
I did this with success. I remember the first time I deliberately broke into a dream. It was a nightmare...in my dream, I was basically being dragged off to be killed. Of course, it felt quite real, as dreams tend to feel. In my dream, I was very afraid, and was desperately looking for a way to escape. Suddenly, my conscious mind LITERALLY jumped in, and I literally heard it say,"Just wake up. You're dreaming." And don't you know it, my dream self thought,"Oh shit! I'm dreaming! I'm safe! I'm waking up now..." And so I did.
That was the first. I had a tendency to want to wake up as soon as I would realize I was dreaming lol. I guess that's the ultimate control lol, simply leaving the dream and waking up lol. But, yes, I was also able to "direct" my dreams within them to some degree.
Edit: I should also mention that I have been able on several occassions to continue a dream I was having after waking up and going back to sleep. Meaning, I woke up, recalled my fun and/or pleasant dream, went back to sleep, told my mind I was going right back.into that same dre, and continued the same dream...sometimes with several awakenings stitching the dream together. Very cool and enjoyable
Edit2: You also might try extending the period of awakening. You know, when you're JUST starting to wake up...don't necessarily open your eyes right away, keep them closed and hang out in that half awake/asleep state for a few.
If you ever awaken consciously but find your body "paralyzed", and your eyes unable to open, don't panic. This isn't uncommon, and the feeling of dread that many people report as this occurs is an illusion. You're safe. Literally just remember that you're safe. Look up "Sleep Paralysis" to learn more.
Let me know if you have questions.
Good luck!
Peace.
