Out of all the scars on his body, half belonged to her. The pock marks on his forearms were from when she had hurtled him into a window, the slight dip in the back of his skull was the result of a hit just a ton too hard, and of course there were the calcite masses on all the bones she had crushed. All were result of his meddling, his comments, his peeping and his too-eager hands. He had nearly received more injuries in civilian life with her than he had on the battlefield.
Tsunade was the strongest shinobi Jiraiya had ever met, and yet, he never shied away from the hits she gave him; he never fought off her revengeful beatings. Yes, he made sure they were well deserved and very memorable, but he accepted her form of punishment in stride. No matter if he was on first name basis with the hospital staff, (that just made him more popular with the nurses) or that Orochimaru mocked him for his limp; he never regretted.
She made him as tough as nails, able to take seemingly unbearable agony without much more than a wince. Tsunade made his skin thick, and that's what he told her when she asked why he enjoyed instigating her so badly.
But of course, that was not the whole truth. Jiraiya endured the snapped bones, purple welts, loose teeth and general chaos let wild upon his body for another, far more important reason.
After she was finished, after her knuckles were bruised on his face and arms tired from exertion, Tsunade would look down on her bloody, beaten comrade with a face filled with justification. That look always drained away. He would have to fake unconsciousness (if it were not reality) at this point; otherwise his reason for the beating would not be realized. Were he awake she wouldn't kneel next to him with a face filled with sudden worry. He wouldn't feel that warm, blue-green touch of hers over the bits of him she had broken. Only when he was insensible would her fingers brush a black eye to bring the swelling down, knit together an arm she had fractured, close a wound wetting his body down with blood.
These touches, the ones of a medic, of a caring and considerate (although guilty) friend were the most wonderful things he had ever felt. Her chakra would dance behind his eyes; beautiful and precise, perfected and soothing. Jiraiya wanted her to break every bone in his body just so that he could feel her hands on him. Tsunade never left him hurting too badly. She tore him apart; she sewed him together again.
But she always left a scar.
GreenBird