Living with my bf and his family

Ok so I'm 15 almost 16 and my bf is 16 in October I'm gonna be going to live with him and his parents in Texas I should probably mention I live in a different state and I'm gonna stay with him for 7 months well my bfs mom is not gonna allow us to sleep in the same room for obvious reasons but see with me living there will be 6 people in the house his older brother his is own room I will have my own room and my bf will be sleeping with his younger brother so does anyone have any ideas on how we could fuck without him getting caught in my room also we could use the bathroom but his mom goes to the bathroom alot at night and the only other bathroom is in his room but this little brother is a snitch so help?