U? Doing drugs?
From the little I have talked with you, you are just a bundle of joy who doesn't sound like she'd EVER get into drugs.
But stop thinking about it too much, because sometimes, overthinking too much on something is gonna trigger something to happen, and at times they don't end up being that good.
Joke about something else ^~^

But if you ever wanna talk with someone, I am here for you :)
I may not be a good adviser, but I'll promise you I shall try my best ^~^

There's a saying that what you think you create , what you feel you attract , what you imagine you become ... so I think maybe it would be better if you can stop joking about it. Talk about something else that is more positive and healthy ? That would keep you from harm .

But you won't do it, will you?

Oh they'll know when you do them. Drugs has severe effect on people if use for long, and once you do them, you'll get addicted and you will use them for long, and you will change, that's when they'll notice something is wrong with you, but you'll be the one that deny it.

Find something else to joke about if you're so worried...

Ultimately - doing drugs is your choice so if you don't have any interest in it, it shouldn't be a concern.
Or you could stop joking about it so much.