Need advice!!!

Kallee • I’m a outgoing fun girl who is in love and wants to go on adventures!

My husband and I talked about trying for a baby on New Years. Now that being said the only problem we will have is his Sister and her family are going to be staying at the house. The problem is that her 13 year old son doesn’t know how to knock and always barges into our room unannounced. I don’t want to be rude so how can I tell my sister in law that my husband and I want the house to ourselves and not offend her?