Cheating With Girlfriends Sister While She Is Next To Me (LONG VERSION)

My girlfriend is hot but her sister is even hotter and a really naughty girl! Last night she sneaked into our bedroom and started teasing me! She gave me a blowjob even though her sister was laying next to us! This turned be on so much! I just couldn't resist and fuck her, just hoping my girlfriend wouldn't wake up and catch us...