This rule is applicable when a female or male writes "lol" more than one time in one sentence to another person consistently. It signifies that this male or female is on said person's dick (metaphorically speaking). As you will notice prolonging the phrase, "lol" sounds like someone is sucking a penis.
Wow he/she is writing "lol" twice in each sentence again and again.
He/she wants you, its the rule of lol.