Luke warm. Maybe room tep.To get it to work,you have to make sure the person is deeply asleep,and you have to make sure the person drank plenty of water before they fell asleep.Good Luck, ;)
you can rub a tomato on it or use baby powder u can also use oil and then after that wash it with very warm water the baby powder i think works the best but that's my opinion tomato juice can help...