The word “psych” is a popular prefix for genre descriptors these days, for better or worse.

Sometimes, “psych” — short for psychedelic, of course — is a perfectly reasonable way to describe an act’s trippy, mind-expanding sound. And sometimes, it feels like bands put “psych” in their bio in hopes of latching onto something, be it ‘60s revivalism, or Pitchfork’s track-review column, or Burger Records’ roster.

So when a band like Portland’s Bath Party comes along, it’s refreshing. There is no faux in these guys’ psychedelia, no ambition in their aesthetic. No, Bath Party filters its jangly surf-pop through gentle psychedelic prism because there simply is no other way.

They go all in, and they do it well, too. Bath Party’s promotional photos are a wonderland of paisley prints and long hair and homemade art, all coated in a bloodshot blur. The cover of its 2014 release “Ep.IV” is a kaleidoscopic collage of flowers and beads and bright colors and Eastern imagery.

And the music therein is a total trip, from the propulsive surf vibes of “It’s a Beautiful Day” and “Invention of Language” to the frazzled underwater soul-punk of “Lunch” to a chiming, ambient experiment called “The Big Bright Eye in the Sky Forgot How to Fly.” Imagine a cassette of The Flaming Lips (circa 1987) playing Ventures and Rolling Stones covers left to warp in some relentless South Asian sun, and you have some idea of what Bath Party’s up to.

Bath Party, with Corner Gospel Explosion and Don Quixote ; 9 p.m. Sunday; $5; Volcanic Theatre Pub, 70 SW Century Drive, Bend; or 541-323-1881.

— Ben Salmon