The morning found master and student, Tsunade and Sakura, on the training fields at the edge of town.
"Sakura! You've got to focus and hold your chakra in ONE TINY PLACE! Not all over your body randomly! And not so big an area! Look here!" Tsunade pointed violently at her forehead in demonstration.
Sakura protested weakly, "But I don't want a tattoo on my forehead…"
"I DON'T CARE WHERE! Focus between your breasts, maybe then they'll grow bigger!"
Scared the old demon would start throwing chakra loaded projectiles at her again, Sakura quickly did as she was told. Focusing on her sternum and above her heart, she focused her chakra until it felt like all the skin would burn away there.
"No! Smaller area! Focus and hold!" Tsunade shouted, goading her on.
After several minutes, the pain lessened, and a curious sense of… peacefulness… passed over Sakura. She felt as though a friendly sun was bathing warmth over her body, radiating out from her chest. 'Oh… so this is what it feels like when it's done right…'
"FINALLY! Good girl, you've got the gist of it now. With time you'll be able to store years worth of chakra in this focus point. It may even save your life someday." Walking over to Sakura and patting her on the shoulder approvingly, she nonchalantly reached over and unzipped Sakura's shirt down to her waist. Grabbing each side, she pulled the garment wide open and bent down to inspect her breasts.
"WHAT ARE YOU DOING!" Sakura screamed and jumped away, clutching her shirt closed again and staring at her molesting teacher.
Triumphantly pointing at Sakura's chest, Tsunade laughingly replied, "Look there, it's proof that you've mastered the technique!"
"WHAT?!" Yanking open her own shirt again, Sakura stared dumbly at her cleavage, only to find… a pale blue star about the size of a dime planted squarely between her breasts.
"…AAAAH!!! Will it go away?? Can I focus chakra somewhere else! WHAT THE HELL! This is your fault!" Sakura tried irrationally rubbing at the spot, uncaring of how perverted the whole scene might be to a passerby.
Almost collapsing for lack of breath, Tsunade eventually managed to gasp out between bouts of laughter, "…no! That's your focus point now! You burned yourself a very special new tenketsu when you succeeded. At least it'll be well protected! Bwahahaha!!"
Infuriated at her sensei, she demanded to know, "…Will it at least make my breasts grow bigger?"
Author's Note: Tenketsu: chakra point. I got this cracky idea from another fic (A Change in the Wind, by SkItZoFrEaK, completely awesome) where Sakura succeeded in copying the Hokage's mark on her forehead. But... After seeing many humorous comics about Gaara, puberty, and 'boobies', well.. here you go. I plan on using this basic idea in my other fic, A Marriage of Convenience, but this is perhaps a little TOO cracky for that (generally very serious) fic. Maybe Gaara will somehow see the mark, and she'll refuse to say just how exactly it came to be there... Anyway, it was a blast to write ☺ Hope you enjoy.