thread I'm going to be gentle here
This, and almost every bicycle indicator be they mounted on handlebars, bags, jackets, wristbands, gloves, helmets, sashes or anywhere else are awful and less clear than a hand signal

As an exception, bike-mounted ones for eg one armed cyclists.
permalink Although in the long and ignoble history of such devices
I don't think anyone has sold a buttplug with turn signals for cycling
permalink But no reason why you can't use both.
Although, you'd have to have very fine bum control to trigger a button on a buttplug.
permalink Good point.
Is the buttplug the carrier for the indicators, or the UI?
permalink both
permalink If it doesn't vibrate too, I'm not interested.
permalink but I think a driver that didn't see you stick your arm out
is unlikely to notice a flashing back pack.
permalink I think the more options they have to see it
the better the chances
permalink whereas I think the difference it makes
is unmeasurably small.