The guilty text is when a boy or a girl stares/flirts/fantasizes about the person/stranger near or next to them and feels guilty for not being loyal to their signficant other and immediately has to text them out of guilt. The text usually includes (but is not limited to) "I love you" or "I'm thinking about you".
In some instances of extreme guilt, the person texting will shout to the people in close proximity to them that they are messaging their significant other.
The guilty text is a coined term because every action has a reaction.
Two people sitting on the bus, a girl and a boy. The boy glances at the girl's low cut top and upon turning away slowly sits a few minutes in silence. After sitting in silence, and a few glance backs to the girl, he whips out his phone and starts to guilty text.
Boy mumbles to himself: I wonder what my GIRLFRIEND is up to.