I used to lie on my left side with my arm out and knees up with bub in the space between...so she had access to bbs and couldn't slip under the covers or wriggle under the pillow.
The other thing you could try is a side-car arrangement. I have a co-sleeper, which is right up against the bed. So bub is right next to me, but has her own space and blankets etc.
I loved the idea of co-sleeping and did it for 6 weeks, but in the end I found I slept better when she was in her own space.
I used to wake
DH when I went to the loo...