"Daddy" made the big mistake - namely: "Beware The Quiet-Looking Ones!" Skipping all the details, by the end, Miyu-chan had (figuratively) drained his balls and (literally) drained his wallet. Another time and place, he would have probably ended up a "Daddy" for real (in about nine months time).
Expressed another way, Miyu-chan used: "Ahh-Ha-Ha-Ha-Ha-Ha-Ha-Haaa ... WIPE-OUT!" (those who know the song from the 1960's would understand).