one day in the bikini Bottom.. Both of you and Xiao had a job in the bikini Bottom as Mr. Crab's employees

Xiao working as a cashier while you cooking the burger in the back, after few minutes, 1 customer arrive and orders a drink and the burger, Xiao gave the order to you as you started making them

you've noticed something about Xiao.. Whenever you both wait for another customer, he stares at you secretly so you wouldn't notice it and.. He was blushing? For what?