In any case, what has given "Hito Natsu no Keiken" its lasting fame....or perhaps infamy...is what has been or not been hinted at in the song itself. It garnered a lot of attention from probably everybody about what Momoe was trying to express through Senke's lyrics....something that was even more heightened since they were sung by a serious-looking 15-year-old in a squeaky voice...some years before her vocal cords would attain that famous lower seen-it-all done-it-all tone. Right from the first line, Momoe blurts out "I'll give you the most important thing that a girl has"; along with the innuendo-laden title (there had even been a previous idea for a title: "Amai Yuwaku"(甘い誘惑....Sweet Seduction), the inevitable assumptions of sexual de-flowering came out, although the lyrics never directly state that there was any sort of seduction involved. Kinda wondering if Senke and Tokura were doing a lot of nudge, nudge, wink, wink while they were coming up with this one. "Hito Natsu no Keiken" was its own PR machine. But Momoe herself would later deny that sex was the "thing"being offered; she insisted that it was magokoro （真心）or sincerity/devotion. When I first heard the song, I didn't know anything about the supposedly racy lyrics....just thought that it was a pretty cool tune. Little did I know.
In any case, the song managed to peak at No. 3 on Oricon and become the 15th-ranked song of 1974. Despite all the suggestiveness (which may have gotten the country's PTAs up in arms with pitchforks and torches), it won a Japan Record Award Popularity Prize and got Yamaguchi her very first appearance on the Kohaku Utagassen later that year. And to top it all off, the single sold 750,000 copies. But most of all, this song was finally the launch pad that got this unassuming girl from Yokosuka into kayo kyoku legend.