It's impolite to overshare details about your bodily functions.
Cory ate something for dinner last night which has now upset his stomach while he's chatting with his girlfriend on the phone.
Cory wants to get off the phone with his girlfriend.
Cory mentions that he must leave due to his stomach hurting.
Cory explains that he has diarrhea and needs to go.
Cory's girlfriend feels sympathy for him and calls back later.
Cory's girlfriend is grossed out by the details.