Prom photos in the ’90s and 2000s had their own uniform, too, Campbell said: hands on hips, or draped around a date’s neck. “Every era has had a ‘this is what looks good’ pose passed around until it becomes reflexive,” she said. “The boob rest is simply Gen Z’s version of a very old instinct: give people a camera and an uncertainty about how to pose confidently, and they’ll reach for whatever pose culture has told them reads as attractive that week.”