What is Jervais?
1.
A jervais (aka a jervon) is a pyhsical and vocal reaction on a whim after some particularly silly and jovial event has transpired.
Specifically, a jervais is a gesture with the forearm beginning parallel to the body and moving across the body culminating in a single arm folding.
Whilst this arm action has occured, the performer of the jervais must contort his face exceptionally insanely (semi closing the eyes) and whilst opening his mouth audaciously speak the words "ehhhh jervais"
It is possible to perform a jervon without the aforementioned hand movement and go straight to the vocal embodiment of the sentiment. (if you're lazy, in a confined space or being subtle)
Also, for subtlety, a gentle arm swing will suffice in certain circumstances.
"I just added a ridiculous word to slangdefine that is actually used for the above reasons"
"Ehhhhhhhhh jervais!!!!!!"
See