Tiny Side Sleeper

Alright mommas! First time mom here, and I have a side sleeper…?

My 5 month old son is the best sleeper. He’s always slept through the night since we’ve brought him home. Well, we just went through his first hard sleep regression, and just ended a long week. Then he started teething intensely. Last night he slept for 10 hours straight like normal again 🙌🏻

My question is, what do some of you recommend to help him sleep on his side better? There’s no laying him back flat. He will fight to get back over on his side. We’ve ordered a size up in his sleep sack, should be arriving this Friday.

I’ve also notice him rotating in his crib like a little clock. He did this before, and we sized up the sleep sack and he went back to back sleeping, while staying in the same place, all through the night.