It helps to really foam up the 1st beer (usually Harp). Give it an inch or more of head. Then slowly pour over the top. My dad had some new gimmick that is a disc that sits on top of the pint with holes on the side that trickles the stout slowly over the top. Worked great for the 1st one, but when splitting 2 bottles to make 2, the 2nd one was not as good. The conclusion was to stick to the turtle spoon.