The truth is:
He probably already told his buddies from high school that xyz girl sucked his cock and he has a pic with a sign to prove it. His buddies said "lets see it", he tells them "err, hmm, let me email her", moves the screen away from them so they can't see anything, and proceeds to make this thread on gfy in a desperate attempt to get the pic he promised his buddies...
(I'm just fucking with you by the way)