There are several methods that can be used to increase the flexibility of grape bunches. One method is to prune the grapevine properly, which can help to increase the flexibility of the grape bunches by removing excess foliage and allowing more sunlight to reach the grapes. Another method is to use crop management techniques such as canopy management and crop thinning, which can help to control the size and shape of the grape bunches and increase their flexibility. Additionally, proper irrigation and fertilization can also help to increase the flexibility of grape bunches by promoting healthy growth and development.