An expression used when a person, or yourself, has done somthing extremely stupid and dopey
Person 1: Dude, I just hit my head on the door.
Person 2: HERP DERP.
A phrase said by idiotic morons who think they are cooler then they actually are.
A sexually transmitted disease contracted from sex with dick mongrels.
She was tryin to slob on my knob, and I was like 'Nah, trick I aint tryin to get no herp derp, get off my dick!'
guy 1: what is that on your lip?
guy 2: It's herp derp.
to act in the way of sexual conduct, and to release tension in the process.
He herped her til she derped.
Go herp yourself.
He derped on her face.
They herp derped