DS starts out the night in his own cot (and DH & I in our own bed). Once DS wakes up in the night, I co-sleep with him in a single bed in his room. That way DH& I still get our time together at the start of the night - but DS doesn't get woken up by DH's alarm in the morning.

The single bed has a rail on one side - so DS sleeps between the rail & me. I've never rolled onto him, but I have bumped him with my elbow when I stretched out in the morning!