Anyway Sangwoo's contact name on Jaeyoung's phone starts with '베' read as 'BE'.
Take note that in Hangul they write words based on it's pronunciation. SO THE CONTACT NAME COULD BE '베이비' which reads as BEYBI / BABY ohmygod im screaming rn imma jump off the clip if my theory is right 
ahjuicy please take care of me too
Now I'm intrigued