How to manage baby thrusting self in every direction??

[spirito]

My baby is 9 months old and has recently starting aggressively falling backwards to get himself to sleep. I’ve always let him self-soothe (in addition to nursing) to get himself to sleep. He’s always been able to either nurse to sleep or shake his head to fall asleep. However, now that he’s more mobile, he’s starting rolling around, sitting up, falling backwards/sideways, then rolling around (repeating cycle) to get to sleep. I’m so worried he’s going to hit his head on the wall or hurt his neck falling against me or a pillow. Anybody been through this before? I’ve been thinking of transitioning to the pack-n-play because of this, but I love cosleeping and still worry about him hurting himself somehow in there.