Tampon in whilst sleeping?! 😫

Annie β€’ Hi I'm Annie! 18 years young and I'd like to think very wise! engaged to my wonderful man ❀️
I have a friend who has told me she keeps her tampon in whilst sleeping..
I'm sure this is dangerous but can anyone tell me if I'm right before I tell her cause I really don't want to be proven wrong πŸ˜•