My ds wet his bed this morning (cot bed) The mattress is plastic one side and a breathable waterproof the other side which is the side he sleeps on. Went to put cover back on matress (which is foam and felt it wet on underside. When i've pulled the mattress completely out underneath it is full of black mould.
I am mortified, not a clue how the moisture has got in there but the underside of mattress is soaking. His chest has been bad for ages and its no wonder. I feel so quitly but had no reason to check it.
So go have a look at yours just in case.