If you want to really spoil yourself or your partner, place the hot water bottle in bed about an hour early -- and then, just before going to sleep, refill it w

If you want to really spoil yourself or your partner, place the hot water bottle in bed about an hour early -- and then, just before going to sleep, refill it with fresh hot water. I find that between the bottle itself and the surrounding sheets and mattress, a lot of heat is absorbed in that first hour. Pre-heating everything should keep the hot water bottle warm until morning. I find this to be an unreasonably effective life hack.