Maybe you know (Patreon)

Guys, I'm a newbie here and I still can't get what is the best way to share boomerangs and vertical videos here. Youtube and Vimeo seem make them horizontal attaching black fields from sides automatically. 

I think some of you may be longer here and may be you know how other people do that. 

If I'm right give  your advice either in comment section or in messages.

Cheers