Best existing comeback to the insult "Suck my dick."
It is often used to test the other person to see if they do present it and if they don't they will be called a "pussy".
If the other does in fact present it, proceed with an insult about his penis.
Andrew: Suck my dick
Evan: Present it.
(Andrew whips it out)
Evan: HAHA! Look at Andrew's little penis!