Stepmother gets fucked to get along with the stepson

Me and my stepmother, we argue a lot, but it is the fault of my half-sister. It is a youporn stupid and I hate it. Today I argued with my stepmother for the same situation, and in a moment of anger I showed her my cock. He left the room, but then returned again to talk with me. We apologized, and asked me why my cock is hard. And I said that I had two days with an erection that I could not calm down. Then I came in mind to ask for help. I asked her to take off her clothes while I masturbate. It was a big help, but it was not enough. I need to pierce them in the pussy. Fortunately I was able to convince her, and fuck her vagina helped me a lot.