Help!

Soo I'm staying with family right now untill I can get my new apartment. But I get really horny on the daily ... and I live with a lot of kids my cousins who are all girls under the age of 15 .. and the don't have doors just on the bathroom .. but it has no lock .. any body have any opinions on how I can get some "fun" time for myself with out any of them accuatly knowing what I'm doing