Are travel bidets discreet enough to use in a public restroom?

Mostly yes, with caveats. Reviewers note that squeeze-bottle designs are nearly silent, while electric pumps make an audible whirring sound that other stall users can hear. Compact electric models like the Bidet Buddy GoFlow and Vikken Go+ are sized to fit in a toiletry bag or large pocket, which is the bigger discretion issue for most travelers.