Marc should use a waterproof floral adhesive to secure wet floral foam to an arrangement base before placing flowers. This will ensure that the foam stays securely in place, even if it gets wet. Hot melt glue or craft glue may work for dry foam, but wet floral foam requires a specific adhesive designed for use with water. Super glue and tape are not recommended for this purpose, as they may not be strong enough to hold the foam in place, especially if the arrangement is moved or jostled in any way.