eavsing - You sneak in on a conversation just to hear what's going on

You sneak in on a conversation just to hear what's going on and maybe drop a comment if they ask. You act like you weren't even there.

I sneaked in on my teacher and heard them say I was the worst. I said I was just taking a break.

I eavsed on my friends and heard them say I was a total disaster. I said I was just eating a sandwich.

I eavsed on my crush and heard them say they thought I was cute. I said I was just checking my phone.