You know that feeling when you finish a companion-quest and you just want to hug him/her because it's been a very hard time?
I see the hug more in a close and comforting way. Maybe it can last as long as you like, by pressing a key in front of your companion. Pressing it a second time would end the animation.
To the slow-dancing mod.
I had this idea when I set up a juke-box in one of my settlements. It only plays one song and it's a slow classical one.
When you're with your companion you could have the option to dance closely in front of it. Maybe by hitting SPACE when it's activated?