You ask Abbie what she means by that

You slowly break off the hug and look Abbie in the eyes. “You always make me happy, Abs. You’re a very cool big sister.” You pause. “But, I’m pretty sure that mom is thinking of me and her making each other happy in, um, a different way though.”

Abbie’s face flushes even deeper red.

You hesitate before speaking again. “How did you mean making me happy, Abs?” you ask her, keeping your voice low and trying to sound nervous.

She takes a deep breath and blinks like she’s trying to hold back tears. “I… don’t want to lose the great relationship we have, Dave. You’re an amazing brother. It’s just,” she shakes her head, “Mom isn’t the only one who has dreams and fantasies about you. This morning, they’ve been all I can think of. I knew I shouldn’t act on them, though. I don’t think I would have even mentioned them to you, if you hadn’t opened up to me about you and mom.”

You nod to her. “I had no idea you felt that way, Abbie. If we’re going to be honest about all this — our deep dark secret feelings… of course I’ve had fantasies about you. I’m a horny teenage guy with no girlfriend, and you’re super hot.” you grin at her.

Your sister smiles wide when you tell her that. Then her expression turns worried. “But, now you’re telling me that you’re thinking of actually… doing something about those feelings with mom. That will definitely change things around the house. You and Mom will be closer. I’m afraid I’ll feel like a third-wheel, left out, maybe... jealous of mom.”

You reach out and brush her hair back from the side of her face. “I’d never want to make you feel any less welcome in our home or family.” You cup the side of her face with your palm. “I love you, just as much as I love Mom.”

She presses into your hand, nuzzling her cheek against your palm. “I want you to love me the same way you’re talking about loving Mom,” she says in a soft, hesitant voice. She turns her head to place a soft kiss on your palm. Then she looks at you with a wicked smile. “If anyone in our family is going taboo with you little brother, I want in.”

You smile and let out a soft chuckle at that. “Wow… that’s a lot to think about, Abs.” You stroke your jawline as if you are considering the idea. “Maybe… I should stay home from school today. I don’t think I could concentrate on classes after this anyway. Let’s go back home and discuss this with Mom, as a family.”

Abbie nods. “That makes sense.” She smiles at you as she starts the car. “When did you get so smart? It seems like yesterday you were just my nerdy little brother.” She laughs. You can’t stop yourself from chuckling along with her.

After she’s been driving a few minutes, out of nowhere Abbie asks you, “Did you kiss her back?”

“What?” you ask, not knowing where the question came from.

"You said mom woke you with a kiss. Did you kiss her back? Or any other time since she started acting like this? Did you ever give Mom a real, man-to-woman, full-on-the-mouth kiss?” she asks.

You don’t see any reason to lie about it, so you nod. “Yeah… I have. Why do you ask?”

Abbie has a faint, sly smile on her face, “I thought so. It was something Mom said… about how you don’t need any practice kissing. It’s because she knows first-hand what kind of kisser you are.” She laughs. “So now maybe I am a little jealous of Mom, or at least curious. I want to know how you kiss, too.”

“Well, there’s one way I can think of to find out, sis.” You tell her with a grin, as she pulls into the driveway of your house.

Abbie parks, unbuckles her seat belt, and leans over close to you. “I knew you were getting smarter, Stretch.” She says in an alluring voice. You slide your hand behind her head, pull her to you, and press your lips to hers. She returns the kiss hungrily. Her tongue presses into your mouth. She moans into the kiss. Her hand grips the front of your shirt tightly.

You hold your sister in the kiss for a long time. When you finally release her so you can both catch your breath, she murmurs, “Mmmmm… mom was right, you don’t need practice. I still wanna practice with you a lot.”

You give Abbie another quick kiss, then tell her. “We should go talk to mom.” You lead her into the house.