Scenario 1: blue is secretly at performer(what type of performer is up to you) at the club in lust's au, lust finds out and they became friends after awhile the star sanses and US!Papyrus Finds out and believes that lust did something to him so they keep him away from lust but, that doesn't stops the two from meeting slowly but surely they start to fall in love 

Scenario 2:

https://youtu.be/EQZ8yiaWeT4

Scenario 3:custom