It has to do with cleavage. Pressing boobs together makes their volume increase, and push them higher which creates more cleavage. They look - Fashion & Beauty Question
What is a guy thinking when he is staring at a girl's boobs? - GirlsAskGuys
What is it with guys and boobs? - GirlsAskGuys
Why Men Love Curvy Women - GirlsAskGuys
Why do men like fake breasts? - GirlsAskGuys
GirlsAskguys Reviews - 35 Reviews of Girlsaskguys.com
26 Signs a Woman is Secretly Attracted to You Even If She's Hiding It
Turn Offs for Guys: 72 Physical, Dating & Sexual Put Offs All Men Notice & Dislike
What is it with guys and boobs? - GirlsAskGuys
Girls, Do you feel jealous when you see a girl with big boobs? - GirlsAskGuys
We Asked 20 Men: Would you date a woman with better abs than you? - Muscle & Fitness
Why do women show cleavage but then get angry when men stare at their globes? - GirlsAskGuys