An album of Black Francis songs inspired by sex might seem unexpected, but it’s never been a taboo topic in his music.

Many of the Pixies’ best songs dealt with knowing someone in the biblical sense -- literally, in the case of “Dead” and “Nimrod’s Son,” to name just two.

It’s a given that an album of erotic songs by Black Francis won’t be the same as one by, say, Barry White, but even by Francis’ own standards, NonStopErotik deals with its subject matter as elliptically as possible.

Rabbits, ferns, and other natural fertility motifs pepper these songs, most of which are reveries inspired by love and sensuality rather than anything raunchy.

“Lake of Sin”’s title is the most risqué thing about it; “Nonstoperotik” is more romantic than erotic, with a sweet melody and limpid guitar solo that recalls Eric Clapton's “You Look Wonderful Tonight,” and “When I Go Down on You” plays like a hymn to intimacy rather than a mating call.

Strangely, despite the album’s concept, it doesn’t hold together as well as some of Francis’ other solo work.

NonStopErotik’s lush sound gives its songs a gauzy feel that works on its prettier songs, but not as well on rockers like “Dead Man’s Curve,” “Wheels,” and “Corrina,” all of which sound like they could have come from any other Black Francis/Frank Black solo album.

Likewise, “Six Legged Man” is a typical but well-done rave-up and “Wild Son” once again connects sex and religion to trippy effect, but NonStopErotik does have moments where it rises above expectations.

With strings, saxophone, and falsetto vocals, “Rabbits” is about as close to a quiet storm ballad as Francis is likely to get, while “Cinema Star” saves the best for last, delivering a hypnotic rocker that sounds more like Sonic Youth than his work with the Pixies or his solo career.

Even if this isn’t some of Francis’ most striking work, it continues the more personal vein of songwriting he began exploring after the Pixies.

NonStopErotik feels intimate in a way that proves he can still find daring territory going into the third decade of his career.