It is important to think carefully before asking your host parents to allow you to invite guests, especially friends of family who may come stay for a week or more.
There are many host families who would not feel comfortable with allowing that and will say no. If they say no, you need to do your best to accept that and not pout or have a bad attitude about it. Remember, it is their home and when they invited you to join them, they were not planning on turning it into a youth hostel.
There are others who might not feel comfortable, but they want to be kind, so they say yes. In those situations, it can hurt your relationship, because they may resent being put in that position. You may get to have your friend come stay with you, but if it hurts your relationship with your host family and leads to a rematch, is that worth it?
There are a small number of families that are happy to allow you to welcome guests throughout the year and have no problem with it. That is a very small number and if your host family is one of them, show them how much you appreciate it their hospitality.
Also, consider how you plan to account for your time during the visit? Will you use your vacation time or do you plan to work and just visit on your off hours? If you plan to work, keep in mind that during work hours childcare should remain your number one focus. I have seen situations where au pairs are too excited about their guest to do their job as well as they normally would. In those cases, the family is giving up a lot. They are allowing guests to stay in their home and accepting a lower level of work performance during the visit. Be aware of that and do your best to carry out your duties and show your host parents that you appreciate their actions.
If you are working during the visit, one way you can avoid letting your work slide, is to encourage your guests to go out and do things while you are working. Since you are familiar with the area you have been living in, you can act as a tour guide. Give them information on places that you have visited with other au pairs and maybe gone for cluster meetings. Since you have already seen these places, you will not be missing out, if they go there while you are working. Then, you are free to visit new places with them in your off hours.
Remember – honest communication, flexibility, gratitude and consideration will make all the difference when dealing with your host parents on inviting guests.