Apparently, Nagatsuki just can't take no for an answer and thinks that Ookuma will eventually fall for her. Stupid girl. I can't wait 'til her bubble finally bursts and the reality of Ookuma's actual intentions become absolutely, positively clear to her. Her delusions are so frickin' annoying.
Even though Chiyo says to herself that she'd rather not meet him again, from that end-panel with those blused cheeks, I suspect that Chiyo is lying to herself (no surprise there), and she just might still have a crush on Ookuma. I guess we'll know depending on whether or not he gets invited to the outing. If she honestly doesn't want to see him, she won't have Igarashi invite him, otherwise...