Misty Meaner - Sharing a Bed with my Hot Step mom

We just drove across the country to go to meet up with the family and celebrate my birthday at the theme parks. When we get there my mom shows me to the room at my aunts house and tells me we have to share a bed for the night. The whole family is here and all the rooms are full. I try to get out of it and go hangout with my cousins but she says no and that we need to get some rest for the big day tomorrow. She comes to bed after a shower and we say goodnight side by side, when my dick starts to get hard she immediately feels it on her ass. How embarrasing. I can't help it, this happens every night at this age! My mom tells me to make it go away but I can't. She tells me to press it up against her and stay still and it will go down. I try that but it still just gets harder! She is getting fed up now and takes my erection and puts it inside her panties and tells me NOT TO MOVE. I can't help it and I start grinding it against her ass in her panties. When she tells me to just put it in a little, her pussy is so tight it almost doesnt fit! She seems to not be able to resist pressing back into me and soon enough im all the way inside of my moms pussy. She loves the way it feels and tells me to be a good boy and make mommy feel good. I cum all over her ass and back and then we finally get some rest