Dude, Where's My Car?
A stoner comedy that spends its whole running time nowhere near this fetish and then, in the last act, merges a group of alien women into the Super Hot Giant Alien and turns her loose. A few minutes of screen time that a lot of people never forgot.Worth watching: The climax, once the Super Hot Giant Alien appears.
IMDb Wikipedia
Giantess Alien & Cosmic Classic Giantess Observer