Self-bondage on a bicycle?

Has anyone given self-bondage on a bicycle a go?? Last week, I watched a Japanese adult film where they mounted dildos to the seats and connected them to the gears. So every time you pedal, the dildo bobs up and down! The scene got me so worked up that it’s been stuck in my head ever since. I’m thinking of trying self-bondage on a bike too. Maybe not as fancy as in the movie, but with the same idea of being impaled. Does anyone have suggestions for how to secure the dildo to the seat? I’d rather not drill into mine; it would be awkward explaining that to my parents… lol.