Sloppy Slug Princess Training for the Betterment of Konohagakure
Somewhere past the middle of Part 1 of Naruto, Naruto wins a bet against Tsunade that results in her becoming Hokage. Through this, Tsunade develops a personal interest in Naruto and devises a plan to use his never-say-die attitude for the betterment of the entire village. For one reason or another, this plan involves siphoning gross volumes of abnormally-thick semen out of his balls with her tits, and preparing him to have other women within the village do the same.
Don't try to tell her it's a bad idea, either.