When you're sobbing or bawling your eyes while talking or telling someone something. You sometimes do this when you can't get a grasp of your emotions yet still want to tell someone something. It's often done when you're too caught up with your emotions and can't stop talking your feelings out. You could be either too happy, too mad, too apologetic, too sad, or too scared, hence the crying, but you still want to tell your side of the story.
You: I can't take it anymore, OP!
Me: What happened?
You: My favorite band is finally having a concert here! *sniff* Waaaaaa! OP, I just wanna *sniff* go to them right now! ahfhjsfhkjhf I wanna but they're ticket already.
Me: Hold your horses right there and cry all you want but don't cry-tell to me about it. My eardrums are about to burst with you cry-telling to me about it.