When Naruto was teaching Konohamaru the sexy no jutsu, they tried to enter the woman's bath/hot springs to test it.
Konohamaru kept going in which Jiraiya saw and he could see that none of the woman would hate him from being a child and being the grandson of the third so uses Konohamaru's form to get close to the action for books.
Maybe he even sucked some tits or pretended not to now what a erection while having one of the woman help teach him.
