I created smiley for happy, sad and neutral event. Any suggestion for sarcasm?
Here is the image for above three expression:
Can someone suggest an icon for sarcasm?
To stay within your existing theme, I'd probably just use a slanted mouth.
Anything more would necessitate rethinking the other icons as well in order to add a bit more definition overall. I think the tongue out is a good idea, but using that for "sarcasm" would add a level of detail not present in the icons you already have.