advice for a long session?

Relaxation, focus and shea butter. Don't expect anything, close tour eyes, listen to your body. If you want something in this practice, It won't happen...

But I think it should be really difficult to relax and focus for such a long time.

I've been thinking of the importance of setting up a environment that cradles me in feeling safe recently for my sessions. This includes no distractions, no interruptions, no cell phone, no chatting, low lighting, pleasant scents, comfortable surroundings in general. Typically I'll ride for at least an hour and up to 4 hours or overnight. I'm tending to break the session up into shorter phases now; start out with a tempo or peridise or a dildo, take a break, and resume with a eupho syn or a pro jr. Needless to say use plenty of lube. :))

I've gone over night a few times. When I wake up, I just do some kegels to wake up my prostate