Police say the suspect approached the girl at Westburn Park while she was walking back to Moscrop Secondary School between 12:30 pm and 1:00 p.m. PT.
The man allegedly engaged her in conversation of a sexual nature before displaying the sex toy and touching her. The girl, who cannot be identified, fled the scene.
Police say they believe the man is also responsible for harassing another 17-year-old girl as she walked home from Burnaby South Secondary School at around 3:45 p.m. PT on Tuesday.
Again, he allegedly started a sexually suggestive conversation, but the girl fled the scene immediately.
The suspect is described as Caucasian, in his late 20s to late 30s, between five feet eight inches to six feet tall.
He has distinct light blue eyes, a slim nose, with a pockmarked face and fair complexion.
Anyone with any information is asked to contact Burnaby RCMP at 604-294-7922, or to remain anonymous, leave a tip with Crime Stoppers at 1-800-222-TIPS (8477) or online.