Think he'll get the hint?
Sometimes 'what's up?' is a rhetorical question. You know how it is, you're out for girls' night at your local dive and some scruffy, clueless soldier comes meandering over trying to spit game. If he says 'what's up?', treat it as a rhetorical (even if he didn't intend for it to be) and pull the hood on the DC What's Up Pullover Hood Fleece Sweatshirt over your head, tighten down the drawstrings, and about-face to show him the skull-and-bow tie screenprint.