Brother Catches Sister Masturbating in Shower

My sister is once more in mom and dad's room, but this time she just wants to use the shower, or more like the shower massager, I record the whole thing on my phone. I get really hard watching her getting off, so with some black mail I have her bent over the counter and then cover her face, I even get her in the eye. The thing is, she gets so wet when I fuck her I think soon I won't even have to ask for the pussy.