DS (2.3) has just been moved on to a cot bed. He is now using his newfound freedom to get out of bed multiple times in the evening after saying good night, and at least once a night. He used to sleep through in the cot.
I've been adopting a method of 'rapid return' since yesterday - minimal eye contact / interaction, just saying "F, bed" and then returning him (and sometimes holding the door closed as he tries to reopen it).
How long till they get the message? I just want to emphasize that he is neither upset nor ill or anything, just stubborn. And softie husband read to him in the middle of the night when it first happened.... I am made of tougher stuff!