Recently I was tripping on shrooms while in the company of three friends, two of which had taken an 8th just as I had. We ate them and went to the beach, some purplish, very dry and crunchy psilocybe. They both freaked once we got back to town, one of them became manic and frantically kept asking for a ride home, which he got within 10-15 minutes. Afterwards he told us he had the worst trip ever in his house and won't be consuming psychedelics for a long time.
The other kid, I don't really even want to talk about. We were chilling (inside my friend's house) and I could tell he was tripping really hard (eg: talking to random objects / plants, laughing uncontrollably) and having a good time. Well as soon as we walked to Safeway (5-10 min walk) for cigarettes he started to sketch out insanely hard. He kept saying every passing car was a cop, well we kept talking him out of it and finally sat down on a bench in front of Safeway.
It seemed like forever as we waited for my friend to buy the damn cigarettes. My buddy was zapped out of his mind & identity at this point, and could not accept what the shrooms were telling him(that his ego was an illusion, as this guy is very self-conscious/full of himself usually). He was running around the parking lot and laying down in random spots, I didn't know how to feel about the situation as I was experiencing full ego loss. I mainly tried to block his actions out while trying to think of how to keep myself safe. He was caught in such horrible thought patterns like I've never seen. As we walked toward my tripsitting-friend's apartment he attempted to grapple/attack people walking opposite us as well as hitting cars in parking lot with people inside/the lights on. He screamed profanities and ran around non stop, my buddy Justin (2/3 his size) barely controlling him, while I walked behind them on a full dose wondering how to make sense of this fucking situation. He kept repeating "This is gonna be great, bro!", "I'm fucking dieing" and "There's the boys right there bro" (like the cops) every 2 seconds.
He only stopped once we got back to Justin's apartment and started playing some music he recognized, plus we gave him the digeridoo to play. But even in there for ~5 min he was throwing shit around and breaking stuff..
Point being, stopping a bad trip is incredibly hard once it happens, and it's best to advise someone not to eat shrooms if you (from experience) can tell that they will not have a good reaction at that current moment in time.