Her Teasing

Since the Covid restrictions have been in force and having gone through two lockdowns, my eighteen year old step daughter Ellie hasn't stopped sexually teasing me.
From saying sexual innuendos, to bearing her breasts, and ultimately sitting across from me and her mother, exposing her pussy to me.
Each day she's either said or done something sexual. And its getting increasingly difficult not to rip her clothes off and fuck the shit out of her.
There's no mistaking she knows what she's doing. Not at all. Indeed I hears her the other day speaking to one of her friends on her phone. She was telling her friend she's watched me masturbate several times and wants my cock in her mouth, her pussy and in her words "So deep up my arsehole".
I knew she'd seen me once having a wank, but apparently that was just the last time.
I do have a reasonably large cock, but have always been faithful to her mum.
The reason I'm masturbating so much recently however, is Ellies mum has been refraining from sex.
I'm not saying I don't find Ellie attractive, I do. It's just difficult as I've brought her up from being six years old. But Ellie doesn't see it that way, not if last night was anything to go by.
As her mother made us our evening meal, Ellie used a banana to fuck herself with in front of me, saying "I wish this was your cock Phil".
Before we ate, I had to go into the bathroom to wank, otherwise I'd have been sat at the table with a boner.
After we'd eaten, my wife spoke to her daughter telling her she was visiting her sister in a few days time. She asked Ellie if she wanted to go, but asked in a way which suggested she thought Ellie would like to stay with me.
Ellie responded by telling her mum "I think it's time, don't you".
My wife simply said "I won't be here honey".
Now I'm thinking my wife and her daughter have agreed on Ellie having sex with me. Either that or I'm reading something else entirely into it.