Bathroom
This dream was highly realistic.
I was in the bathroom, which was brightly lit and normal in all respects. I had just taken a dump. I stood, turned, and glanced into the bowl. It had quite a bit of tissue in it (not unusual) with the shit pile dumped in the middle on top of it. The shit was a light, almost yellowish brown and rather soft.
I prepared to clean myself, but something didn't seem quite right, and I felt I needed to check something. At this point I partially woke up, partially opened one eye and confirmed that I had been in a dream. I was lying in my bed normally.
At this point I checked with my body and found there was no urgency to visit the bathroom, so I went back to sleep, abandoning the dream.
When I got up and visited the bathroom, I did a dump of about the same size, but there was very little tissue in the bowl, and the pile was of a slightly firmer texture and a little darker.
The really interesting thing about this dream, is that I somehow suspected, while I was in it, despite the total realism, that it might not be reality, and then was able to deliberately contacted my waking consciousness to confirm that.