When TWO people creep on each others facebook pages constantly.
Includes straight liking one anothers pages and commenting on every post/picture/status dating back to the day they became facebook friends.
Person 1: John is constantly straight liking Hillarys facebook.
Person 2: Yes, but Hillary comments on all his status updates.
Person 1: Oh so they are into the whole mutual creeping thing. Why don't they just exchange phone numbers?