Here’s how we do it:
Get Zoom and have your friends also get it. It’s free.
Start a meeting in Zoom and a room in Watch2gether.
Send links to both to your friends.
One of you (whoever makes the rooms) will be hosting it, which means the one making the playlist on watch2gether.
while someone is singing, everyone who isn’t singing should mute their mics.
song requests best sent via chat.
A few notes: the more friends you have at once, the more likely it is that lag will put song out of sync. I have not found a way around this, other than to not have too many people on at once. Also you may have to search a bit for a good copy of a karaoke song, as major karaoke companies block their youtube videos from being watched through watch2gether (like karafun)