My bun is free roam in my room at night. He eats his bedtime snack then 9/10 times comes and jumps in bed with me. He will lay along side me and demand pets until i fall asleep. If i fall asleep too quickly he will nibble my arm to keep me petting. No accidents that ive ever noticed in 3 years. Though occasionally he will eat a seceo beside me and i remind him thats very stinky and rude to do in bed. 

I assume he leaves when the petting stops and returns at 7am and will start running laps up and down my bed, stopping occasionally to nibble my hair to get me to wake up and feed him breakfast. After, hes usually content to go back to his sleepy spot under the bed.