It’s by Kanon Wakeshima and it’s called Lolitawork Libretto. ♥♥♥
Sorry for not replying sooner!
I use the old version of the embed on youtube and then I make it small so it’s just the play button and volume. To make it autoplay you add &autoplay=1 at the end of the video URL. (I hope that makes sense and that is what you asked for.)
It’s appearing as a post? That’s strange! :o