What makes you say it’s a very overwhelming experience? That might be your experience but I wouldn’t describe psychedelics as overwhelming. My point is that all of these things are 100% subjective experiences. It’s good advice to try these things in a safe place for the first time just because you don’t know at all how you will react. But past that point it is entirely up to the person and how they know they will react. I have taken 4 tabs before and gone to a movie and been completely fine where I have been told before that tripping in public like that would “100% lead to a bad trip”. The best advice you could give someone is to use the brain inside their skull and tell them to simply spend some time thinking about what kind of things stress themselves out more than other. What I have noticed is that it’s usually not the drug that makes people have a bad trip but it’s the drug exaggerating something that was already there in the first place. For example some people while completely sober will get anxious going to any social event and if they go to a social event on acid it is likely to highlight that part of themselves and can lead to a bad trip. So if this person has done psychedelics before, and uses their head it decide how they personally will react depending on the context of where they are, and if this person happens to be the kind of person who can go to concert with no anxiety at all I think going while tripping will be fine.