Are saying to just feed one then wait till its down and feed another? or are you saying to put the head of the 2nd mouse in the snakes mouth as he is finishing the 1st so he will take both down at the same time? Feeding him one and then waiting till its down and feeding another is not a problem that would be fine. The other method is used when people are trying to switch a mouser to rats and should be used for that purpose. Some BPs that never get switched to rats grow up to eat 4 or more adult mice in a feeding. He will be fine