This video was made by me, in my home, using items that I own. I own all the copyrights, commercial rights, and the worldwide distribution rights to this video. Don't know anything about ink? I've leaned a little about the subject and will share with you what I found out. The syringes in this video are not hypodermic needles, they are blunt ended craft needles that can be purchased from hobby shops, craft stores, etc..
To listen while using other apps, switch the player to Picture-in-Picture (PiP) during playback — it keeps playing in a small floating window (the screen stays on).
To listen with the screen fully off, in-browser playback stops by YouTube's design. Open the video in the YouTube app to keep listening where background playback is supported (e.g. with YouTube Premium).
Open in YouTube app