"Tch, no," she scoffed and wriggled her way out of his hug to smooth her ruffled hair with an annoyed huff. When would she have the time to help plan a party and, more importantly, who would actually trust her to? Pepper knew better than that, and Tony should've known that Pepper knew better than. Cassie was insulted on behalf of them both, really.
"I'm just here for the free food," she explained, then added, "And you. Happy birthday." She got that part over with as casually as she could, since she knew how little he probably wanted anyone to care about his birthday, so she'd pretend it didn't matter for his sake (even if it totally did). "Anyway, it's a pretty good party, so you should be nicer about it."