I think I'm being very a bit PFB but my 9 month old has taken to holding a muslin as he goes to sleep. All well and good apart from he likes to rub it against his face and then falls asleep with it covering his entire face. This is ok isn't it? 
I feel so stupid asking (hence asking on here!) but when I see him like that I instinctively want to grab it off his face and feel a bit panicked 
It's only a small Tesco muslin so nothing big enough for him to get wrapped up in or anything.