I have no idea why this happens to me, and often dont even know it until the next day when someone tells me-- but I am a sleep fucker.
The first time it happened was about 8 years ago. I woke up balls deep in my ex wife, and exclaimed "whats happening!!!". She had thought I was fully conscious, and was freaked out that I'd been asleep the entire time. It happened about 6 more times over the course of my marriage.
Fast forward to now and its happening to my current g/f once a week. Its crazy and disorienting as shit! She just texted me today about my alter ego's exploits last night...
Apparently, hes actually a much more passionate lover! Wtf!?