I slept once on the mats. I literally remember feeling like I was in a fuzzy and comfortable dream and waking up to my partner shaking me and asking if I am alright. I blurted out something like "What are we doing?" and I was wondering why my partner was sitting next to me and where I was and what was going on. But not in a panicked or concerned way. Like some parts of my brain knew what was happening. But the thinking me was trying to put together all the sub-conscious streams again and get them routed correctly.
Turns out his cross collar choke was tighter than I thought. It was not unpleasant and I had a mild buzzy/headache-y feel for the rest of the day. It all felt a little dreamy and is one of the strongest memories I have had in recent years. Definitely something I remember clearly.
Also: if anyone is in the Denver area we have mats at our office :)