You're going to have to step up and tell your friend that although you value her friendship, you will not tolerate her sons behavior in your home. If he can't follow directions and behave, he is no longer welcome.
Meet your friend at HER house or at a public restaurant only. Your home is off limits to her son until she can train him to behave appropriately.
Is your friend clueless about her son's behavior? Spitting milk & throwing oranges is more than impolite, it's uncivilized. Tell her she's welcome but must get someone to keep her child if he's going to act that way in your home.
I agree boundaries for the child in YOUR home of meet them somewhere where it wont cost you stress and breakage......the smart mouth in me says.....buy a taser...but ....yeah......sounds like your friend needs to learn how to discipline the child cuz if yall think its bad now.....wait 10 or 15 years and you can take a day trip to the prison on visiting days....WOW!!
Set boundaries. Once they are crossed, end visits and forbid future visits until tighter boundaries are held.
Ask her to take him and leave,Tell her she's welcome any time but she will have to have a baby sitter for the child at home, If she is giggling at him, she is encouraging him.when he gets bigger she will be very very sorry because by then his lack of boundaries may become dangerous to himself and others.
Get on of those pet containers for 'traveling', put it in the corner ( bathroom, or ba<x>sement somewhere - out of the way ) and explain to the little 'darling', that "that is for him when he's at your house, until he learns some respect". Buy a padlock for it, & use it. It may or may not take awhile, but "he will learn". It's not cruel or nasty, it's called 'isolation', they do it in prison to 'visitors' who think rules do not apply to them.
Several people have been severely prosecuted for that.
Well.. if its too unbearable to have him over and be having that happen... you might want to tell his mother that he can't come over if behavior like that will happen. It is her responsibility to have her son under control in another person's house. It also might help her realize that she needs to take action here, because he is causing problems to other people.
I would allow her in as long as the kid behaved. When he starts acting up, ask her to take him home, now. Either that, or meet at hers. People end up with no friends when their kids are like that.