An aquarium seal has a primary seal(between an edge and a face), and a secondary seal(A 90 degree seal from face to face). When resealing(i do this for extra cash) one would surly be cautious not to penetrate the primary seal while stripping the secondary seal(90 degree corner bead). I most definately "press the new bead into the corner with a single fluid swiping motion from one corner to the opposite. I start with the bottom four seals, then the vertical seals, then if needed the upper seals.
I have most recently sealed a 115 gallon, custom aquarium, and had the owners recommend me to others who called(months later but...), a raw/unpressed bead is NOT the correct way to relieve the barometric stress from a 90 degree seal.