In bed or on bed
"In bed": I eat my breakfast *in bed*.
Here is some more info: http://ask.fm/The_YUNiversity/answer/124985032578 (Scroll down to the bottom about "on my bed" and "in my bed.")
Here is some more info: http://ask.fm/The_YUNiversity/answer/124985032578 (Scroll down to the bottom about "on my bed" and "in my bed.")