More cathartic than fake swear words (Frick! Freak! Fetch! Dangit! Got dandruff!) is the actual act of saying a swear word. Nothing in Mormon culture, however, matches the sheer ecstasy of being able to say a swear word, and have it not count as a sin.
The Bible is replete with examples of scriptures where tweens and teenagers will giddily giggle as they quote verbatim:
Abide ye here with the ass. (Gen 22:5)
...And the ass turned aside out of the way, and went into the field: and Balaam smote the ass, to turn her into the way. (Num 22:23)
He told us plainly that the asses were found (1 Sam 10:16).
Indeed, some studies have found that up to 17% of trips to the Bible Dictionary by teenagers are to find "that one verse in the Old Testament where they say the word ass", although these statistics are up for debate.
Some other examples of socially acceptable swearing for Mormons are:
Quoting someone else who said it (especially to express shock or outrage that the word was uttered in the first place).
Quoting J. Golden Kimball.
Parents saying something because “We said that back on the farm.” The S word is a prime example of this.
Swearing after age 75.
Saying it really quietly, while no one else is around.
Scaring kids straight (Stake Presidents swearing at their son and his friend after shoplifting is completely sin free).
Parents swearing at kids for bad behavior
While the latter example has not been accepted as full doctrine, it is generally acknowledged among Mormons that there must exist some loophole for parents with respect to their childrens’ behavior.