Cover the bubble with an old t-shirt. Set your iron to medium heat and press it into the t-shirt until the flooring underneath is warm.
Cut the bubble from one end to the other with a utility knife. Scoop flooring adhesive onto a putty knife and cover the exposed subfloor with the adhesive.
Press the edges of the flooring in place and use the old t-shirt to wipe up any excess adhesive. Cover the spot with a sheet of wax paper and set a heavy object, such as a paint can or a stack of books, onto the wax paper.
Leave the object there for 24 hours. Remove the object and the wax paper. Apply a bead of seam sealer over the seam and let it dry according to the package directions.