Any person (need not be present) that is the go-to "butt" of any joke. In any situation, whether it be at a classroom, party, funeral, etc., this person's reputation can ease the thickest of tensions.
Yo, Dick is the scapejoke of the school. All you have to do is say his name, and other people laugh cause they know what's up.
An SJ may be performed at the end of any job (such as a blowjob or handjob). Just before climax, the giver of the job will suddenly and without warning, screech like a howler monkey, thereby giving the receiver a feargasm.
When you make a mistake or miscalculation and rather than take responsibility you simply blame your colleague, Bob. Akin to scapegoating, just with a specific target named "Bob".