Wife's Niece Caught

We were invited to my wife's sister's house for a party in the evening. that night when getting there everyone was drinking and having a good time laughing and playing some games. About an hour in my wife's niece how turns 20 in a week her boyfriend shows up. My wife asked me to get something from the car and at the same time her niece and BF get up and go downstairs and honestly at the time I thought nothing of it. While at the car I see a light turn on in the basement window so out of curiosity I obviously look to see what is happening. I see the boyfriend standing there next to the bed whick is about maybe 6 feet from the window...alright then as I turn away my niece comes in the room and they start making out. now I'm interested so I watch a bit longer which I'm glad I did. The making out quickly turned into her pulling his shorts and undies down to the floor, taking her pants off and grinding her ass on his dick while he stood there rock hard. Now I thought they were going fuck like rabbits but instead she turned around got on her knees and starting sucking his cock. I was kinda in shock and hard at the same time because I want to watch this and she is doing this like 20feet from a family gathering. She sucked that cock pretty damn good even trying to deepthroat it. Suddenly he took over stroking him self while she sat back on her feet looking at him and he unloaded a massive cumshot onto her face and i mean the kind you see in porn it's was huge. It covered her face,in her hair, on her tits, on the bed next to her but she wore it like a champ. Eyes closed cum covered face sucked it again for a second slapped his cock on her face all with a smile and enjoying herself. I returned to the party with the shit from the car and my wife asked what took so long and all I could say was I thought I saw some lightning and was watching for a bit