Perhaps Andy Samberg and his Lonely Island crew aren't the right people to teach you about semicolons. In this hysterical performance with Alanis Morissette on Jimmy Kimmel Live, the funny guys get their grammar completely wrong.
Now if you want to know how to properly use a semicolon, here's an example:
Andy Samberg misuses semicolons; other people just avoid them completely.
In this sentence, we linked independent clauses with closely related ideas.
Okay, there's your lesson for the day. You are officially smarter than you were yesterday.