When Alison Johnson put her 18-month-old Caleb down for a nap, she had no reason to believe her son was in any danger.
But the US mum was shocked by what she discovered after hearing Caleb cry out from the room he shares with twin sister Libby.
Now she has issued a warning to other parents of twins, or two children close in age, about the danger of placing multiple cots side by side.
"I have a lot of friends that have twins or kids close in age that may have a similar set up, so I wanted to share something VERY scary that happened today," she wrote on Facebook.
"This morning I put Caleb down for his nap. Shortly after he started to cry. After a few minutes, I went in to check on him. He had climbed out of his crib and was stuck between his crib and Libby's crib.
"His body fit through, but his head wouldn't. He was using every ounce of energy he had to hold himself up by his little arms. If they had given out, he would've just been hanging there by his head."
Alison said she can't bear to think about what might have happened if her routine hadn't been slightly different than usual on the day she found Caleb between the cots.
"What's even more scary is that like many moms, I generally use nap time as an opportunity to shower. Had I done that today and checked on him after five minutes, he would have literally hung himself.
"When baby proofing, I never in a million years would have seen this as a potential danger. Please consider sharing this post in case someone you know may have a similar set up.
"It's incredibly heartbreaking to think of what the outcome could have been today. I'm still totally shook up over it and don't think the vision of him stuck there will ever leave my head."
The post has been shared more than 45,000 times since the concerned mum wrote it earlier this month.
Commenters have thanked Alison for sharing her frightening experience in the hope it will prevent other children from being injured.
"So scary!!! Ours used to be set up like that in our old house and I never would have imagined that could happen. I'm so glad Caleb's ok. Sharing now!!" one fellow mum of twins wrote.
"So scary!! Something very similar happened with our little guy except for he got stuck between the wall and the crib. thankfully my husband went in and checked on him but it is a very real fear that We have as well!" commented another.