A phrase used by the character Ted and his band on the popular television series "scrubs". This is a short hand version of "I'm rubber and you're glue" implying someone's insult bounces off of you, creating a "boing" sound and is thrown back through the air making a "fwip" sound. Boing fwip is often accompanied by hand movements implying said action.
"person 1: You're a jerkface
person 2: Boing fwip!
jerk face (formerly known as person 1): Oh snap"