What would it mean when a guy sings in front of you?

Okay, so I may be looking at this wrong but really. I sit next to a guy that would be humming and randomly sing out loud," girl, I need to get your number" something like that and sometimes I turn and find him staring at me. Plus I sit on one side of him and his friend on the other.
Updates
+1 y
And there is no other girls around and I don't ever see him singing any other time.
What would it mean when a guy sings in front of you?
Post Opinion