Investigators said John Rodriguez, 20, Santa Ana, drove his black 2009 Toyota Camry up to the curb next to an 18-year-old student on Tuesday.
They said he asked the student a question, causing her to look into the car and see the man exposing himself.
The man allegedly made a "vulgar statement" and drove off.
The girl was texting her friend at the time and typed in the car's license plate number into her phone.
She told authorities, who then tracked down the suspect.
Detectives want to know if there are other incidents. Fountain Valley investigators are also looking into whether or not Rodriguez is the suspect described in two similar incidents earlier this year.
Anyone with information was asked to call the Westminster Police Department at (714) 548-3207.