I bought a homeless guy a pack of cigarettes and then asked him if I could smoke one with him. He gave me one and sparked up his lighter for me. Then he asked me to sit down on a little brick ledge in the tunnel we were in. He then lit his cigarette and took a single drag, then proceeded to set the cigarette down on the ledge and stick his hand into his boot. From his boot he produced a pipe for freebasing either crack or meth (or something else who knows?), heated it up to vaporize whatever drug residue had accumulated on the walls of the pipe, and took what seemed to be a relatively small hit. There was still a large amount of vapor in the bulb of the pipe, but he cooled the pipe down with his hand and I presume the vapor condensed back onto the walls of the pipe. He stuck the pipe back into his boot and closed his eyes, grunting occasionally. I thought maybe he was about to go psychotic, but eventually he opened his eyes and made sure to tell me that his eyes were now open. He then started wavering like a spinning top that was about to fall over and an expression came across his face that was a sort of mix between "I'm about to puke" and "I'm about to sneeze". I stood up and stepped back in case he sent a biohazard my way and he said to me "I'm not going to bite you". I talked to him for about 20 minutes before leaving him. I'm not sure if I will buy a homless person a pack of cigarettes again, especially in boulder.