Family Ties/Leave and take it out on your mom's pussy.
Though jerking your cock while watching what's happening between Jake and Heather holds some appeal you can't argue that fucking a nice tight pussy and having a big set of tits to suck would feel a whole lot better. Knowing that your mother is currently on the couch, playing with herself, waiting for you to come and have your way with her, makes the choice an easy one. You adjust your rock hard cock and pull your shirt off and toss it in the hamper before slipping quietly out of the bathroom. Secure in the knowledge that with Heather and Jake busy with each other they sure won't be bother you and your mommy in the center room of the R.V.
You slip around the corner to see your mommy laying on the couch just where you left her, with one side of her bikini top pulled down and her breast exposed and her bottoms pulled to the side to reveal her shaven pussy. She has her eyes tightly shut as she pounds three finger into her pussy with one hand while twisting and pulling roughly at her exposed nipple. As you get closer you can hear a symphony of moans escaping her lips as she plays with herself. Out of the corner of your eye you also notice that Jessie has moved from the passenger seat to sitting in your dad's lap. Because of the noise of the R.V.s engine you can not make out what is being said between the two of them but Jessie's jeans shorts are on the floor beside the driver's seat and she appears to be giggling hysterically. It seems that you won't be disturbed by Jessie either.
With your mother moaning, on the verge of climax you walk up beside the couch and lean down to give her a passionate kiss. It takes her off guard so she doesn't immediately return your lust but after she opens her eyes and realizes it's you, she grabs you by the back of the head and drives her tongue deep into your mouth as she moves a hand to your throbbing cock.
"Oh Timmy, where have you been..." She moans breathlessly, grabbing your shorts and yanking them down, releasing your throbbing cock.
"Never mind.., I don't care, just fuck me baby. Mommy misses your big cock in her pussy." She begs, pulling the other side of her bikini top down to her tits are now completely exposed while holding her bikini bottoms to the side to offer you access to the pussy you came from.
Never one to disobey your mother you quickly slip between her legs and jam your cock into her sopping wet cunt with ease, causing your mommy to climax right on the spot.
"Oh god Timmy, I can't believe how good you fuck me." She groans as you establish a solid rhythm with your hips while taking her left nipple into your mouth and start sucking on it.
"That's it baby, suck mommy's titties, fuck mommy's pussy. Fuck! Do what ever you want, just don't fucking stop!"
With the feel on your mommy's pussy milking your cock, the sight of your big sister completely naked and your twin sister in her bikini on your dad's lap, you can no longer hold back your need for release. Your cock begins to swell and your mother pulls your head deeper into her tits and locks her legs around your hips.
"Oh yeah! do it baby. Fill mommy's pussy" She demands, setting off a chain reactions that ends with her pussy being hosed down powerfully by your orgasm. She moans and coos through the full minute it takes you to cum. before turning your hips loose and allowing you to pull out from her well fucked cunny. Tiredly you slip up her body slightly and lay down on top of her as she encases you in her arms, pressing her big boobs against your small body in the process.