Farting is always fun, we know dis. One might argue that it’s not fun when you get more than you bargained for, but that would be a shart, and it’s in a category unto itself. Barfing is never fun.

So, if x represents farting and y represents barfing, we get the following equation:

x•(-y)

The solution of which is:

-xy

Now, I’m no mathematician, but that looks generally negative, so I’m going to say that fartbarfing is, at the very least, not always fun, though I would argue that it’s probably never fun due to the inclusion of the barfing.

Class dismissed.