When one laughs so hard that their mouth goes very wide open and the corners of their lips become highly rounded - so that when viewed side-on, their lips literally take the shape of a taco shell.

If you manage to get a side-on image of your friends taco laughing, it is guaranteed to become a crowning meme in the group.
Me: Why did the chicken cross the road?
Friend: I don't know, why did the chicken cross the road?
Me: TO GET TO THE OTHER SIDE!!!!!!!!
Friend: OMG HAHHAHAHAHAHA -Taco Laughs-
Me: -Takes picture, posts it on group chat-
Friend: Oh no did you take a picture of me taco laughing?
Me: Yeah I took a picture of you taco laughing!
Friend: Ugh my mouth is in the shape of a taco in this image!
Me: Yup, that's why it's called the taco laugh!!!
by Lefty Power 123 July 7, 2019
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