Do you mean you put baby in cot, you walk out of the room and they calmly go to sleep? My ds falls asleep in his cot as long as I am stood there- little or no crying and sometimes lie him back down. I can't seem to get past this stage- a while ago he went back to sleep after waking hourly from 7 ish but has now apparently lost that ability. He is 11 months and we co sleep from 10/11 ish usually.
I just wonder whether everyone means the same thing when they say their baby 'self settles'- it doesn't always seem to equal a good night's sleep.