Co sleeping advice - mattress

[Chaispice]

Just looking for some cosleeping advice. I’ve got a medium to soft mattress, I can’t afford to replace it and surely most people aren’t buying new mattresses specially for Co sleeping?! Assuming at least some other people can’t afford a new mattress, did you do anything to make it safer? I saw an Instagram account that recommended a yoga mat under the sheets to make it firmer. Has anyone tried this? Just any yoga mat? Or did you do something else?

A hopeful bump
or do I stop worrying about the mattress?

we have a Japanese floor mattress futon, with yoga mats underneath. The mattress is around 10cm thick. This is used for myself, dh and toddler, firmer mattress or floor is good for back but I found my hips actually killed me so we went with relatively softish Japanese futon.

then we have a travel cot to the side of the mattress and dc 3 months in there so kinda like a cosleep /side crib situation

hmm we have a pretty new bed. So I can’t really replace the mattress at this point. I never intended to co sleep so I didn’t think it would be an issue. Your set up sounds ideal though!