You may remember the above photo from one of my previous posts.  I call what Apollo is doing as corpsing as he literally looks like he has died. When a bunny does this it means they are relaxed & happy.  They don’t have a care in the world. Of course this behaviour has completely the opposite effect on their human carer, words like heart attack, hot sweats & panic come to mind.
Many years ago when I first came across it my heart practically stopped until I could see the bunny breathing. Now I still nearly have a heart attack but quickly look for signs they are breathing usually through the camera in the bunny shed or by quietly approaching & watching.  The last thing you should ever do is speak loudly or touch them, the shock could end up making them a corpse.  Apollo is the bunny who takes the crown for being the corpsing bunny at the moment. Here are a few instances: