Sarah's hips were flying as she continiously pounds into you, your asshole was feeling numb from her thick shaft gliding in and out of it. The pleasure you feel somewhere deep inside you makes you hardly notice it, though.
"Fuck, your hole feels amazing Doug," your sister says, an almost innocent smile on her face, "I can't get enough of it!"
To your surprise she seems to thrust even harder and faster. You can feel her fingers digging into your legs which she uses to mercilessly pound into you and with every thrust you hear her balls slam against your ass cheeks. More and more moans escape your lips involuntary.
"See Doug, you're getting into it," your mother taunts you.
"mmmh~" is the only sound coming from your throat, in too much pleasure from the deep dicking you receive.
Sarah never stops her assault and over time she manages to find all your sweet spots. Every thrust sends a wave of pleasure through you building up with the last.
You take a look at your little sister joy written all over her face, her hands under your knees, holding your legs apart. Her breasts jiggling every time she moves back and forth and lastly her 10 inches of meat shortly visible and then disappearing in your butt, stretching you. You have to admit that it's a beautiful sight.
The pleasure gets overwhelming as you enjoy this view and feel her hot rod deep inside you. Your own little dick slapping lightly against Sarah's stomach, unused as it is. It is emasculating, but strangely you love it. That's when a last loud moan escapes your lips and you come, feeling pleasure you never felt before.
Throughout your orgasm Sarah is continuing her thrusts, sending more waves of pleasure through you. "Ohh you really love it, don't you Dougy?," your sister says, "I'm so happy, but I'm also getting close!"
Having said that Sarah picks up her pace even further, rocking your world as everything around you becomes a blur.
Hard, long thrusts slamming into your ass. You hear your sister moaning as she is nearing her orgasm.
"I'm cumming~~~!"
With a last powerful thrust she hilts herself deep into you. You feel her dick expanding and the her hot seed marking your hole as her territory. A never ending stream of thick semen pouring into your bowels, every pulse sending an additional jet.
The sheer amount of cum she is pumping into you makes your stomach slightly bulge.
As the last pulses subsided, Sarah lets out a contented sigh. Pulling her pole out of your ass, a river of cum follows from your gaped and abused pucker.
"That was the best Doug," Sarah exclaims, "I hope we can do it again."