Gf takes large draws from her cigarette and holds the smoke a few seconds before exhaling. is this worse than smoking the normal way? or no difference

It's probably ...: ...a little worse. The smoke with its tars and carcinogens has a little more time to come in contact with the cells in the oral cavity and potentially contribute to a problem. This would be a very small difference, however, and the tremendously greater concern is smoking at all. All efforts should be directed at assisting Gf discontinue smoking altogether! Good wishes:)