When you send a text and you wait anxiously for a reply. Mainly when sending to a person you are interested in or apologizing for a ridiculous action committed the night before in a drunken state.
8:30am -{You} "Hey (insert hot chick's name here), nice meeting youlast night. Lets go out for a drink later this week."
9:00am-
10:00am- {you mention to your friend} I texted the hottie I met last night when i woke up this morning and she hasn't responded.
{friend} Damn bro, you got some serious ATA (Awaiting Text Anxiety). She probably was so drunk she hasn't got outta bed yet.