DS is 5months and a terrible sleeper. will not however hard I try sleep on his back for more than 40mins (normally about 15) He will however sleep blissfully on his tummy 
I don't want to put him on his tummy as like every parent I'm worried about SIDS but equally he normally sleeps on me which again is a SIDS risk.
He can't roll over yet but can lift his head right up from lying down and hold it up for a few seconds.
Any tricks on encouraging him to roll so he can get onto his tummy on his own?
We have a movement monitor but apparently you can't resus a baby who has SIDS (morbid I'm sorry) so that's pretty much useless.
What did you do if you had a tummy only sleeper?
Any tips for getting him to stay asleep on his back?