Make it worse.no sex for a long time then make Elena punish her and make her watch elena and mars having sex
Force her to have sex with Erin while at it!
By the way...
Random Dude: I have just noticed that you hate that Erin, why not break up with him and fuck the consequences?
Cecille: BECAUSE WITHOUT HIM WHO AM I GOING TO TORTURE!?
Random Dude: Your lover Mars? Or maybe Sera? Or Elena? Or maybe Vi? Ah! I know! I have a lot of slaves that I bought from that crazy Free City folks. I could bring up one similar to Erin at a low cost! Cheap easy! We will even decrease the slave's cock size for a more faithful experience! Or perhaps a demon if you prefer? Various options!
Megacorp! YOUR FUTURE IS OUR PRESENT!
Mars: ...for...god's sake...you...you literally commodified dick enlargement drugs and...reducers!? Wetware Slaves?! AMPUTATION!? What the fuck is wrong with you!?
Random Dude: The wonders of a new high tech age. New ways to improve life and new ways to disturb and traumatize lifeforms! A great time to live in! So Cecillia? Wanna a bulk of Erin lookalikes?
Cecillia: ...So Mars can be cloned as well...hm...that means I don't need to care if he dies.
Mars: ...I...Erin...come here...I need to make that psycho fall in love with you again!
Erin: NO! NO!
Mars: I WON'T BE KILLED BY HER AND CLONED! IT WILL BE YOU! COME ON! NOW!