Both are in two different classes and because Heeseung's class always end first, he waits for you infront of your classroom. Your friends teased you because Heeseung offered to carry your bag

In the Cafe Heeseung and Aeri sat down together and act as if a couple

Sunghoon: "The friends only couple is sitting down again"

Sunoo: "Are you guys really together? or what?"

Jay: "Yeah... it's confusing at this point"

Jake: "mhm"