You set the plan into motion

"Alright, lets do this."
Lydia lays down on her bed and grabs her phone. "I´ll text John and hope he comes online quick. I can help you get hard in the meantime. We dont need you hard for the next step, but I like to have something to play with."
You unzip your pants, while Lydia begins to texts John.
She takes a break as you finish undressing to look at your semi-errect dick. "Fuck you´re big. Alright, get over here."
You lay down next to her, and her hand wraps around your cock, beginning to jerk you off.
"Ah, he´s online. Here we go."
You watch their chat while Lydia continues to play with your dick.

Lydia--Fuck, I´m really horny

John--how come? gotta watch out, at the table with the others

Lydia--Wore no underwear while Ethan hailey and i had dinner

John--what?? fuck thats hot. is Ethan still there?

Lydia--wouldnt you like to know ;) want proof?

John--yes!

Lydia--careful no one sees though. although maybe you´d like that

Lydia takes her hand of your dick for a second. "Sorry, just wait, this will be worth it." Then she positions herself and takes a selfie showing her bare pussy under her dress, you just out of frame. Your heart jumps, as you just now realize that Lydia actually wore no underwear the entire time. Your dick hardens even more, and you see some pre-cum on the tip. Lydia quickly moves her head forward, and kisses the precum of the tip of your cock, then she makes herself comfortable again, your arm around her shoulders. You watch as she sends the picture to John

Lydia--like what you see?

John--you´re so hot.

Lydia--i think im gonna masturbate now, thinking about Ethan, and how he might have seen a glimpse of my pussy, fully exposed...for him

John--...

Lydia--you like that idea?

John--...yes

Lydia gets up again. "Alright, lets not make Hailey wait any longer," She goes over to grab the strap-on, and wraps it around your waist, adjusting it, so that the fake dick hovers under your real dick.
"Fuck, how are you bigger than the strap-on? Thats so unfair, I really want to feel the real you. Either way, lets continue, we have a crowd to please."