"Now that we're family, let's all go for a bath together!" The opportunity arose at a "family bathhouse." Unexpectedly, the stepson also wanted to join in…! The older man, taking advantage of his wife's inattention, instantly became erect. He and his wife, along with his stepson (who has developed large breasts), enjoyed a stunning hot spring trip. The older man's penis and the woman's large breasts were mutually attracted, and they had intercourse countless times. (MIDA-453)