I usually only use the heat pads if I have to transfer it to my pocket for awhile. Otherwise it stays in the 98 range for a couple hours if I just stick it in my crotch.
If the temp is a little high when you pour it into the collection cup just blow on it.
If the temp is a little low rub your thumb against your clothes for a couple seconds then hold it against the temp strip, when it syas 98 walk out of the room,