Rose had fallen asleep curled up there with the Doctor, the day having passed them by. She was now wide awake, but she knew the Doctor needed more sleep. 
"oh I got you a toothbrush." She said as he came back from the bathroom. She dashed into the dinning room where the discarded bags from her earlier shopping still lay. Rose dug out the toothbrush and offered it to the Doctor. "I thought that if you needed one it'd be in the TARDIS and..." she trailed off, no use explaining her train of thought there.