Getting Caught at the Wrong Time

So as a horny 17 year old , I would often snoop around my parents room, looking for anything to get me off. They had these drawers under their bed and in one of them I found a DVD of some nasty porn. I grabbed it and immediately  ran across to my room , forgoing shutting the door. I thought I had plenty of time to rub one out. I pop it in, sit on my floor, pull my shorts down revealing my cock that was diamond hard.   I press play, drippimg precum in anticipation . The porn starts off with some lame storyline, but then it gets real nasty. Girls are rimming  a guy's  asshole, sucking him off.  I'm stroking harder and harder as they continue their fun. I cum buckets after a few minutes .  All of suddenly, one of my best girl friends is in my bedroom door. She sees me with my fun covered hand and cock, asks if I need to finish. I (stupidly) said no and she went back downstairs to await me.  She had apparently texted me but my phone was in my shorts, so I never felt it vibrate. She got a good kick out of it, but I wish I asked her to help me finish.   I have seen her naked enough times that it has helped me jerk off many times.