I have heard of students saying ‘come on baby!’ in the class a couple of times.
First time was last year in one of my 5th grade classes. In a writing practice, one of the students skillfully fit in ‘Come on baby!’ into one of the speech bubbles in their story writing. Then, some students, especially females, started acting the the roles in the story and said it in an absolutely flirting, emotive way. I was instantly stunned! At that moment, I just thought it was an isolated case so didn’t try to figure out the reason behind. Anyways, there can be thousands of reasons, such as a recent movie or cartoon in which ‘come on baby’ was said by one of the crew. So I didn’t give a damn about it until I heard it again another time yesterday in another class. A couple of 3rd graders came out with exactly the same expression while they were trying to get their teachers come to their seat and check out their work.