Bart was confused, then started to grin stupidly when she hugged him and wrapped his arms around her in return. That felt nice. He liked hugging Kara. And that she liked hugging him, apparently.
Emboldened by the fact that he had managed to get a girlfriend (a super great girlfriend at that), Bart leaned over and pressed a quick peck to Kara's cheek, his own cheeks only turning a little red.