There are reasons why some side projects are … side projects.

During breaks from his main gig as Queens of the Stone Age frontman, Josh Homme becomes Carlo Von Sexron (the choice of the name will soon make sense), the drumming half of Eagles of Death Metal. His counterpart, childhood friend Jesse Hughes, takes over guitar and songwriting duties as sex-crazed scumbag Boots Electric. On the band’s third release, “Heart On,” Hughes shows his ability as a guitarist and is able to successfully exaggerate — often to hilarious outcomes — the scuziness of 1970s rock ’n’ roll. Despite humor, the album is far from memorable.

Despite the misnomer, Eagles of Death Metal play what critics have referred to as “scuz rock.” On “Heart On,” Hughes explores such topics as dancing in the club with foxy ladies, the glamour of Los Angles and tight pants.

“Solo Flights,” an ode to self-gratification, is an ironic take on the sex-crazed songs of the ’70s. Hughes wails “What the sitch is/ I scratch what itches/ Bravo self-gratification/ No one does me like I do/ I’m just a one-man operation.”

Funky guitars and female oohs complement the testosterone fest. On songs such as “High Voltage” — with its heavy wah-wah — filth bleeds from the speakers. The guitars sound like they could be the background to a high-budget porn film. They probably will be sometime in the near future.

In stark contrast, the album musically is nothing to scoff at. If not for Hughes’ convincing (yet still unique) take on ’70s funk rock, the lyrical content would mean nothing. His playing is surprisingly versatile, as he melds dirty funk rock with other influences such as hard rock more akin to QOTSA and a variety of classic rock influences. For all the fun he pokes at ’70s rock, he sure knows what was influencing the musicians of that time — the riff on “(I Used to Couldn’t Dance) Tight Pants” might as well have been an alternative to Jimmy Page’s bluesy playing on Led Zeppelin’s “Houses of the Holy.” Homme is steady as a skinsman, and although accustomed to the limelight in his main gig, is wiser than many actual drummers. He knows well enough not to overplay in order to bring out his counterpart’s contributions.

Yet the good guitar playing and ironic subject matter cannot mask the simple, unmemorable rock songs. “Heart On” lacks the depth and complexity of Queens of the Stone Age’s latest release “Era Vulgaris,” and compared to the music that EADM reference, Hughes’ vocals are nowhere near as memorable as any of the singers he mocks. After the initial chuckle from the album’s subject matter has worn off, there is little to keep the listener coming back. Or to warrant anything more than a minor but devoted cult following.