Chosen Solution
So I have a Bose QuietComfort 35 and I know this is 25 but there’s no guide of 35. Anyway, the right ear side, the piece that holds it together to make it turn light and right, it broke and now the right earpiece is just dangling around.
Heres the Headphone
Pull the ear cushion and let get a better look. I’m specifically looking at the white looking ring around the bottom of the post attached to the upper piece. It looks like broken plastic to me and I would like to what it was attached to. All you may need is some super glue to rebuild it. This guide should work: Bose QuietComfort 25 Ear Cushion Replacement
@lazypanda sorry but you cannot fix this. There is always a chance of purchasing a broken set from online auction houses or local pawnshops, garage sales or wherever people try to get rid of their broken stuff. You can try and find a new yoke and replace that with yours. Of course if you know someone that can do 3D printing they could make one for you.
weirdly I have the exact same problem with the right side. It did not fall or was pulled. I was trying to put it on just like I always do (owned the qc35 for 2 years now) and it just broke. Surely a design flaw.