I'm secretly jerking next to my stepsister

I lay down next to my stepsister and started masturbating secretly while looking at her. At first, I did it through my underwear, afraid that she or someone else would notice me. But then I couldn't hold back any longer and took out my uncircumcised penis and kept masturbating. I wanted to come on her, but I was afraid she would notice what I was doing, so I came on myself.