Exactly, you detailed out exactly what I had in mind!

Though uh... I'd say maybe emphasize the idea of consent, not 'platonic'.

Some people can seperate sex and love and friendship in their approaches to relationships, but lets be real, the vast majority of people cannot, when any kind of sexual touch is involved.

I would say probably don't involve people who have uh, genealogical relationships to anyone else in the group, probably try this with a group of fully informed, explicitly, enthusiastically consenting, open minded adults.

Don't peer pressure people into this.

Find open minded, kinky "freaks" instead, lol.

Personally, I'd put this on about the same tier of group activity of strip poker or drunk/strip twister.

You'd also have to have some kind of ruleset to say like, each other person can only send a total of XX seconds of vibration per song, or something like that, maybe more complex rules if you want some 'gameplay' in that regard.

The good news though is that simple bullet/egg type wireless vibes can be pretty cheap, maybe $25 or less.

The bad news is that everyone is gonna need to be ok with potentially pissing/shitting themselves, especially if people are also drinking, and they've not used such vibrators before too often.

This would probably be easier to pull off at someone's home/apartment, unless you can find a private karaoke club thats ok with people potentially pissing/shitting themselves on stage.