trying to convince my ds1 that he wants to sleep in his big boy bed at night, but he won't! the problem we have is his brother is needing to go into his cot - at the moment sleeping in a crib but nearly out. tried all sorts of things except putting my foot down. sleeps for naps in it. don't want to have to insist because very good at bed time and sleeps very well, but if i do, will i mess it all up... anybody with experience please - what do i do????