my ds every morning told me that he heard people breathing in his room at night, and that 'they' would lift the covers by his feet and poke his lower legs and ankles, and breathe by his face. This went on for a long time. I used to tuck a blanket around the bottom of his duvet, all tucked in, but still he says it happened. I put it down to too much Scooby Doo...
He was about 8 at the time. Then youngest, prob aged 3 had two 'friends' who came to visit him at night, so who knows...