spending the night..

hey guys! so i live w my aunt and my cousin is coming home for the weekend which means he will be sleeping in MY room, i dont want to sleep on the couch or on my sisters bunk bed bc both are hot and uncomfortable. me and my bf have been together for almost 7 months. i’m 19 and he’s 18.. i want to spend the night at his house so how should i go about asking in this situation?!

pls respond!