I never intervene in a feeding. The snake can figure it out on its own.
Sometimes they start off taking it wrong, but will switch it around. Others times they drop it and start over.
I had one bp that ate butt first for the longest time. I just figured the butt was the tastiest part of the rat... never eaten a rat so I cannot say.
Just let the snake do it's thing, and it will figure it out in time.
Bruce