Stepmom gets convinced to have sex with her stepson so he can make sure her sex is good enough for her husband

I am newly wed to a wonderful man. And it just so happens I have a wonderful stepson too. He so much wants my marriage to last with his dad, that he was willing to help me make sure I did sex stuff well enough to keep my new husband happy. I think I did ok but he gave me a few pointers too! I was so relieved to know he was there for me in such an important way. Now I feel confident my new marriage will last.