The truth of body figures

The guys suck in their stomachs in front of pretty girls to look like they're skinny, but once the girl leaves, they exhale and expose that they are obese. With the girls, they bend over to hide their boobs when they see an unattractive guy. But when an attractive boy approaches, the girls stick out their boobs to look like they have big boobs. Then the plot twist, that "attractive dude" was actually holding in his stomach in front of the girls... Sorry if this was long /:

Ahhh, thank you.