Continual Humping and fleaing now baby has arrived

Hi All,
I'm a newbie here and after some ideas.
My beautiful Jazzy is nearly 2 and usually has pretty good manners, she is so loving and is so spoilt.
My adult daughter lives with us and since her baby has been born my Jazzy has become very "loving" towards her, especially after eating.
When Jazzy has eaten and comes back inside she immediately humps my daughter with a lot of force. She is pushed away and told no but she keeps coming back for more. She will sit on the lounge next to my daughter and slowly gets closer then starts to flea her which leads to humping. This behaviour is becoming constant and she occasionally does it to me but listens if I say no!
I'm guessing this has something to do with the arrival of my grandson and is probably a jealousy thing.
She still gets heaps of attention and is allowed to sniff bubby whilst we are holding him. She is inquisitive and only sniffs and nudges a bit. We have introduced my grandson from only a couple weeks old and he is now 3 months, we want them to be friends as she is a big part of our family.
Can anyone let us know why she is acting in this way please?
Is it just a matter of telling her no and ignoring her?
Thanks in advance
Lenore

Hi and welcome, do come and say hello when you get chance   

https://staffy-bull-terrier.niceboard.com/f7-new-member-introductions

This is not something I've experienced but does should like it could be an attention thing,  ignoring is the answer to a lot of unwanted behaviors so thats all I can suggest really. Not sure if these links help at all?

http://staffy-bull-terrier.com/Introducing_your_dog_to_a_new_baby

http://staffy-bull-terrier.com/mounting_and_humping_in_dogs

Perhaps these are helpful? Is she spayed? Does she have irritation on her genitals, perhaps?

http://paws4udogs.wordpress.com/2013/12/02/why-dogs-hump-spoiler-alert-its-not-all-about-dominance/

http://dogcare.dailypuppy.com/causes-female-dogs-hump-things-2676.html

http://hubpages.com/hub/Why-Female-Dogs-Hump