What I mean exactly is let's say I wanted to nap right now, how long would it take for me to get into SP? (I'm really tired)

I'm not talking about entering REM. (I know that takes 90 minutes) I just mean SP. I wanna see if I can experience it during a nap so I can finally see what it's like, and be prepared for it tonight.



I have another question, let's say I've done WBTB and I'm in SP, after it's done (or happening) and I can't move, what do I do next to enter a LD? Some guides say to roll.....but how can you roll if you're in SP? do they mean imagine rolling, like visualizing it?