Well when you ask for gas, they turn it on at the main unit, then you hold it and suck on it as you need it! So it is self controlled, but just needs to be switched on first! Bath the next day usually because everyone is so tired and bonding etc, it can be on the same day just depending what you want to do, but there is no urgency in it. It can be done after a couple of hours or whatever, but depends when you give birth I guess