can you get arrested for being on drugs?

i’m going to beyond and i like to dabble in MDMA every now and then, but the thing with me is when i’m on mdma, i get very excited and it’s quite obvious im rolling. i am also a very anxious person and i was wondering if a cop so happened to see me getting lit, would they be able to arrest me even if techinally i do not have any possession of drugs?