This must be a frustrating situation, so take a deep breath. Count to ten. Then, remind yourself that you are living in your friends’ house.
The bad news is that when you live in someone else’s house you really do live under their rules – just like Mum used to tell you. But the good news is that if your friends really are on their computers all day they may not realise what is happening with their children.
Suggest to your friends that you’d like to take them out for a cup of tea or a drink and have a chat about your living arrangements. When you are in neutral territory, employ the “sandwich method” of discussing the problem by sandwiching your complaints in between two compliments. For example, thank them for allowing you to stay with them but then mention that there are some concerns you’ve had in the past couple of days/weeks/months. Discuss your concerns fully, but avoid simply listing your complaints. Offer solutions that you think might work for the current situation. Then finish your discussion with another compliment. Something along the lines of “I just wanted to discuss this with you early so that I know where you stand and we can move forward in a way that you are happy with.”
Be warned, however, that the way forward really will have to be whichever way your friends decide. Of course it would be nice if your friends take into account your feelings as their houseguest, but at the end of the day it is their house and their family.
Hopefully you and your friends will be able to reach an agreement about how all of the children in the house should act towards each other, and how you will each engage in disciplining the children. It may well be that your friends don’t feel it is your place to discipline their children, or their place to discipline yours. If you don’t have general household rules in place already, use your chat as a chance to hammer them out so that every adult and child will be on the same page about what is appropriate and what is not.