Affirmative.
StrangeBedfellow
Somehow, I generally tend to not sleep for very long in that position, can't quite put my finger on it...
What I like about my brain is the amazing capacity it has to provide me with erotic dreams during my sleep that I subsequently only remember in parts. I'm going to guess that you would figure in one of them in some way.
Any preference? Finding one that doesn't leave marks can sometimes be a challenge. A decent set of lined cuffs seems to mostly work OK, hands work pretty well too, but then they're not free for other things, and I haven't yet become tentacular! Mixed success with straps, depends on the softness and width of the material. Whilst I like the use of rope, I'm fussy about looseness and some people really mark easily with it, even with the softest ones.
It depends on the country and possibly also where in that country. Fairly common in my experience in the Netherlands, Germany, Austria, and Switzerland, and maybe the Scandy countries where you often get two mattresses instead of a single double. I don't recall ever having seen them in the UK or Ireland, and in France, they're more of the exception than the rule.
As a bystander, I applaud you.
I was just passing through, what a treat!
In my experience, you need to get up close and personal, just like the guy behind you.
Take mine too, he's not the only one!
Nah, keep them cumming!
He struck lucky!
Two thumbs in reciprocating movement.