I used to do this with my classes (teacher training) and it always showed up on my teacher evaluations post-course as one of the highlights mentioned by trainees. You can do it too with students.
Play the song below and ask students if they know about it. Then, get up and go around the class giving everyone a free hug and saying what you value about them. You can also do it with online teaching! Just go around the class sending a hug icon and using the chat button to express your value of other classmates.
It really works. Students even wanted us to do this EVERY class. This guy has some ideas for virtual free hugs!
Get the worksheet for this song on ELT Buzz Teaching Resources.