Made him imagine growing breasts

"Then let's test it." Dr. Valentine said and looked deep into John's eyes. "Look down your body and imagine your chest expanding into huge tits."

John looked down his flat body. Everything looked normal. But than he started to imagine small breasts growing on his chest. First just two small mounds started to show on his clothes, then they got bigger and bigger. He was surprised by how real it looked to him, despite he still was as flat-chested as usual.

In his mind the breasts grew bigger and created a beautiful cleavage. But that didn't stop them. They got so big and round they stretched his shirt. But even there they didn't stop. For John it looked like he had grown two big balloons on his chest, which were now nearly bursting his shirt. But just a second later it really burst, revealing two unnatural big and round breasts growing out of his chest.