I have fallen asleep with a heated throw blanket. They also make electric blankets for your bed. My parents use theirs all the time. About 30 minutes before going to.bed they will put theirs on high. Then once they are in bed they turn it down to a lower setting. The blankets are made for sleeping under, and not like a hearing pad that can (and will) cause burns if you stay under it it too long.
I am kinda weird though. The heat for short term helps but if I leave it on too long it can cause my muscles (etc.) to actually hurt more. So I have to be careful.. But then again caffein makes me sleepy. So yup. I am weird.