My little Princess(Chihuahua)

Question
I need some help with my little chihuahua, Princess, when we play in the floor she tends to get a little rough and attacks(biting), but when I am ready to pet her she immediately attacks, how can I make her tell the difference, she also attacks my youngest son, he's 5, when he tries to pet her she growls and attacks, she never bites hard but I want to prevent that from happening.

I also have a questions about pooping in the house, I take her out to do her business and she always pees and after we circle the yard a half a dozen times she does not poop and is readt to go in, and just as soon as she goes in she heads to the kids room or bathroom and poops, why and how can I make it stop? Please help!!!

Answer
for the bitting the best thing to try would be to use a water bottle spray her and tell her 'no bitting' loud and firm,even in a small dog this is a serious problem

If that doesn't work,try calling some trainers and ask for advice

Now for the house training the best way to solve this is to use a crate,and how you do that is to keep her in there at all times,except to be let out every few hours,to go out somewhere to play and to et,and do that for about two weeks and then slowly let her out more,if she goes back to making acidents,back in the crate she goes for about ten days