His sister is drunk, then fucks the boyfriend

last night my sister came home completely drunk. I could hear everything from my room. I know that she wanted to fuck, but when she started masturbating she has fallen asleep. The guy tried to wake her but did not move. I could not leave my brother-in-law to be desired, and without sex, so I went into the room to finish what he had started and my sister. I went into the room and I approached him. He already knew what I wanted. Made me oral sex while my sister was still here next to it. Then I turned and gave him a blowjob, but my sister was like one dead. So I’ve ridden and I fucked up be satisfaction. The day after my sister woke up without knowing what had happened.