My labrador whines and sits by my mom and taps her with her paw?

[Abby]

I have this lab, and we have no idea why, but she will go up to my mom while she's sitting on the couch watching tv, and she will sit reaaaally close to her (shes on the ground) and stare at my mom. She will sit like that for maybe a minute, and then she will start to whine and put her head in my moms lap. Then she will start smacking my mom with her paw. My mom will look at her and give her attention, thinkings that what my dog want, but then she will continue doing it. We check her food and water to see if shes hungry when she does this, and we try to let her outside to do her business, but no matter what, she instantly goes back to my mom to whine. She doesnt do it 24/7, and she only does it to my mom. Shes doing it more frequently now, though. So anybody have any ideas WHY she is doing this?