The song doesn't have anything explicit, but it uses a lot of euphemisms.
R-15, the show that proved sex sells, but was also a character study on the nature of genius, living up to expectations, and being comfortable with your own talents. However, I'm here to provide you character songs. I don't need to say who's singing on each album - the characters do a fine enough job of that.
Each album includes either the OP or ED, both in TV size and sung by the quartet on the album, the eyecatch music, four character songs, plus those four songs in instrumental and karaoke versions.
Utae's song was actually used in the show, as her hit single. All the rest weren't, but still fit their characters' selves very well. Note that, except for Taketo and Tsukuru, this is the first time singing solo for these voice actresses. Best of luck to them in the future.
MAJIYABA - Taketo, Fukune, Ritsu, Ran
HIRAMEKI - Utae, Raika, Katsuyo, Tsukuru