It's just I'm a ftm and trying to figure out what's a danger and what isn't and what is one of those lets scare new parents so much they don't wanna put their baby down anywhere things is impossible

i used one with my kids and it was wonderful.

Call and check if you're worried but I loved mine. My girls were very snotty babies and it helped a lot

This one goes under the sheet

Yup you put it under the mattress...or maybe under the sheet? (if I'm thinking of the same thing), and it helps baby not get congested. I had one for my girls