Come on.. It's not that Heizou thinks you're dense, quite the opposite, actually- but how have you still been so oblivious to his pining? He thinks he's always been obvious with you, even to the point where his other friends would take notice. But apparently, not you. Maybe you were deliberately ignoring his flirtations? The idea made Heizou frown, though he doesn't think you're someone who would do that, either. There has to be some way he can imply his feelings without outright saying it...
It was probably childish, but he's really been wanting to try something he's seen online. The only problem was that it was relatively intimate, but what better way to be forward than this?
During lunch, Heizou decides to take a little detour by slipping off campus to the nearby convenience store, scanning the shelves of snacks with purpose. He selects a box of chocolate pocky biscuits, purchasing it and quickly heading back to the campus before the late bell for the class after could ring.
Since he shares that class with you, it's the perfect opportunity to propose his idea. And even luckier, the teacher says they're behind on grading papers so they're giving the class a free period. Once they're done talking, Heizou follows suite with other students dispersing to either catch up on late work or flocking to their friends and quickly slinks from his desk to seat himself in the empty chair next to yours, holding up the box of pocky with a mischievous smile. "Hey! We're both caught up with our work, right?"
He opens the box and the subsequent package, choosing a stick of pocky to eagerly flourish. "Let's play a game! Since we both have nothing better to do," Heizou's tone is smooth, intent on persuading you to indulge him. "Have you heard of it? It's called the pocky game, wanna play?"