My girlfriend sister walk in just cought me humping my pillow

Well just a few moments ago pass 10 pm I was alone in my bedroom laying fully in clothes in my bed with my door open I never close it any way I was rubbing my very hard cock up and down very slow then fast on my body pillow ass going down up back in fourth side side I was rubbing it good against the pillow I look up with my eyes only seen her my girlfriend twin looking twin sister looking right at me her big brown eyes looking hard I ack as I didn't see her I keep on rubbing my Cock it turn me on much more noing she was watching me play I begin to flip over on my back cock string in the air I started slapping it she rhen walk said let me help y sucking me all night