A man secretly shows off his erect penis to a girl who came to a hot spring on a family trip. You'd think she'd blush and be embarrassed, but she's curious about the man's erect penis, which she's seeing for the first time! The girl isn't satisfied with just looking, so she starts touching and licking it! The man erupts when the girl gives him a handjob and blowjob that he's not used to! Unable to hold back, the man caresses the girl's still-developing body, and even engages in forbidden sex...