Not the way you expect.

Jenna's expression is unreadable. She looks at you sharply as she grips Tara by the shoulders.
"So, you're not interested in her at all, James? Not tempted?" Her tone is flat.
"No, Jenna. I didn't respond to her flirting or teasing. She's telling the truth."
"...doesn't do anything for you at all, this pretty young thing?"
"Jenna, please... I told you she doesn't."
"Not even when I do this?" She turns Tara towards her.... and proceeds to make out with her right in front of you.
"Jenna! What the hell??" you don't know what's happening right now. Is this a test of some kind?
"Still nothing, baby?" Jenna's smiling now. She stands up with Tara between you, and puts a hand under each breast, squeezing. "Nothing at all...?"
You can't deny the bulge in your shorts, and Jenna's smile gets bigger. Tara's face is scared and confused.
"Well, since we're confessing things tonight..." Jenna slides her hands up over Tara's tits, never breaking eye contact, "I should admit that I've had a little crush on this one since she walked into my class in March..."
"R....really, Ms. Jenna?" Tara turns to look at your wife, and Jenna kisses her again.
"Yeah, sweet thing. I...haven't been with a girl since high school, before James and I..."
"What?! You were..." Wow. You never would have guessed.
"I experimented, James. Tara," she turns the girl to face her. "Thank you so much for your honesty. That was really brave. But...." She looks over at you, and bites her lip. "Would...would you be willing to suck James's cock for me?" Her face reddens.
"Are you serious?!" your voice squeaks in a very unmanly fashion.
"Yes. Don't worry James. This isn't a test. I... I want us...I want to..." she's having trouble actually saying it.
"I know what you want Jenna. I'd be happy to help..." Tara's voice is sultry now. She turns and sticks her tongue in Jenna's mouth, pawing at her tits and moaning.
"Take....take his cock out..." Jenna pants as Tara explores her neck and chest with her lips. "Suck my husbands cock, you little piece of pie." Jenna sits on the bed, opening her robe and reaching into her panties.
Tara needs no second urging. She bounces over to you, practically dragging of your shorts.
"Turn sideways and come closer, I don't want to miss a thing."
You obey numbly. This is a dream, You're going to wake up soon. Its just a happy little dream. Tara's mouth around your cock lets you know that it certainly isn't.
"Oh...fuck....."
She's bobbing and slobbering in no time, and you stare at Jenna's face as she schlicks herself in time with the bobbing little tart.
"Oh god... she's so hot...and so are you baby. I love this! It's as good as I imagined!" She's panting now. "Slick him up nice and wet, Tara, because I've got a pussy that needs a dick!" She strips off her panties, laying back and spreading her legs.
"Can I..." Tara breaks off to look at Jenna. "May I... prepare you, too, Jenna?"
"I thought you'd never ask, Tara. Come here." she crooks a finger, and Tara dives from one set of married genitalia to the other. In seconds, she eating Jenna's snatch like a veteran muff diver.
You move over to where Jenna's head is resting, and lay next to her, kissing her. She grabs your head and returns the kiss passionately.
"I love you, Jenna. This is crazy!"
"I know! I love you too! This is going to be fun..." a wave of joy hits her. "Oh you little kitty cat. Where'd you learn to eat pussy like that?"
"Nowhere, Ms. Jenna. It's my first time."