Thank you for all that you do. I have waited until my baby is 8 weeks old to co-sleep in a queen sized bed with myself only. I have followed your guide on safe sleeping. My baby is asleep on his back, but his head is titled into the side (from breast feeding) and when I move it back he wakes up. Can he be on his back with head on the side?

Red Nose does not promote co-sleeping, but recommends that the safest place for baby is in their own personal safe sleep space.
“The safest place to sleep a baby is in their own safe sleeping place in the same room as an adult care-giver.”

Red Nose supports a risk minimization approach. & includes the following information about avoiding potential risks:
“The risk (when co-sleeping) is significantly increased in the following circumstances:
Where babies are less than three months of age
Where there is adult bedding, doonas or pillows that may cover the baby
Where the parent is overly tired (difficult to arouse)
Where the baby can be trapped between the wall and bed, can fall out of bed, or could be rolled on”

Download Sharing a Sleep Surface With a Baby - please read for full information & risks.
https://rednose.org.au/article/Co-sleeping_with_your_baby

Do you have adult bedding in sleep environment? eg doona/blankets/pillows?
If his head is tilted & resting against your breast (or anything that might decrease air flow eg other soft, padded objects) there may be a risk, however, we are not aware of any general risk when head is tilted to side.