Blackmailing my Big Step-Sister Into Fucking Me in the Back Yard

I overheard some commotion outside the residence, and upon investigating, I discovered my elder step-sister Kat in a predicament while attempting to exit through her window. Kat has been confined to the premises for a while, and she is prohibited from leaving. I make it clear to Kat that in exchange for my silence, she must fulfill a certain request of mine.
My desire is solely fixated on engaging in sexual activities with Kat. I stipulate that for me to keep quiet, she must engage in intercourse with me right there in our backyard. My step-sister proves to be compliant and even exceeds my expectations, readily succumbing to my desires.
I proceed to ejaculate inside her tight genitalia, gratifying my carnal urges.