I do the same thing. I smile at the most inappropriate times, but not because it's funny. I feel your pain

Some people just have other ways of coping. Sorry op

Just make sure your friend knows the issue

I have that too. I've had situations where I am so uncomfortable that I absolutely cannot stop laughing which always makes the situation worse. Try to find something else to focus on. I try to think about things that stress me out like bills so I can try to control it a little. Now that I have a son I use him as an excuse too. For example if we see something that makes me uncomfortable in the store and I start laughing I look at my son like he just did the funniest thing.

I know that feel, OP...I also sometimes can't stop it, even in extremely inappropriate situations....for example when you're on a school trip to Auschwitz concentration camp :'/ I got so many dirty looks...

Wow, that's unfortunate.. anxiety can have unfortunate ways of representing itself

I have the same problem. It's horrible, I know. I cover my mouth and look down and try to cover my face if I can. If I do it well enough it kinda sounds like I'm trying to stifle my crying and no one realizes that I'm actually laughing. That way I can seem like a normal human and not a psychopath.

I giggle when I'm nervous too and it's really really embarrassing. I feel bad for you OP. I hope no one noticed

It's a curse. Hopefully the nervousness calmed enough to explain yourself. Not everyone gets it isn't done intentionally. I remember when i laughed because my boyfriend was pissed off at something i did and i chuckled... Which didn't look good.

I did that at my grandmas funeral when I was a kid. idk why lol