Terence has mentioned this phenomenon of a dream DMT trip in one or few of his talks.
Anyway this is how it went about for me.

1st dream trip - This trip happened based on a trip report I had read on erowid.
The report went something like..the person is in his room smoking DMT with his cat. And after ingestion, he looks at his cat and sees it has a third eye.
And ages later, one night while sleeping/dreaming, I become lucid and see a cat with a third eye staring back at me. It was hazy but felt very DMT like.

2nd dream trip - This is the real mindfuck. The dream trip goes like.. I'm in my high school and someone gives me something which I quickly vape(which I presume is DMT). And the next moment, I actually blast off! And then I'm in a pool of exploding, rotating, blissful colorful fractals. The mindfuck is not only that I actually blasted off to the DMT realm in my dream but I have never seen fractals in a psychedelic trip before that dream. It definitely felt like a DMT trip and can go as far to say it was one.

Sounds amazing. I always wondered about this ever since I heard the story by McKenna about it happening. I think the interaction between DMT and dreams, particularly Lucid dreams could really be explored and developed a lot more.

It is not an every night experience, but for me, I remember several occasions in which I was dreaming that I was tripping on the molecule.

Sometimes, I have experienced full-hit breakthrough, and all that entails.
Other times, I have had, shall I say, more manageable experiences.

I actually find it quite pleasant.

The brain produces its own DMT so I'd think that's what happened..??