my stepsister in the bathroom

She always went into the bathroom when I was masturbating and stood there looking in the mirror and pretending she wasn't seeing anything, but deep down she was already doing it to tease me and today I had to tell her how horny I felt whenever this happened and I just said that at the same time she called me to fuck her right there and I didn't waste time... I took my cock out and punched my half-sister's pussy in the bathroom.