HELP!!

HELP!

I need some advice. My little Squish has taken to wriggling around in his cot while he's asleep and regularly gets himself wedged across the cot. By regularly I mean every hour at least, through the night. As you can imagine, I am now running very low on reserves and I can sense than my pnd may soon raise it's ugly head once more. I'm exhausted, quite honestly. 

I will welcome any suggestions you can make as I can't think of anything that is safe other than putting his mattress on the floor or putting him in a narrow box at night! 

We have a really long bean filled sausage we bought off the net that was advertised as an alternative cot bumper. It was ok initially but now he is more mobile he somehow, manages to get tangled up in it!