Sarah is tired of watching.

You are so absorbed with Crystal's cock that you don't notice Sarah kneeling behind you. You are startled as your pants are suddenly pulled down and you feel something pressing against your asshole. You look over your shoulder, letting Crystal's cock slip out of your mouth, and see Sarah with her hands on your hips trying to ram her cock inside you, but your sphincter is clenched too tight, denying her entrance.

"Whoa, Sarah, take it easy. You don't want to hurt him." Thankfully, Crystal has come to your defense.

"But I really want to fuck his ass. It's just so cute and I'm so horny watching you two."

"Of course, but it's his first time, so you have to do it right." You look back at Crystal in shock, feeling betrayed. "What? I'm not okay with this." Giving your sisters blowjobs is one thing, but do you really want to lose your virginity to them?

"Don't worry, we'll be gentle." Crystal replies.

"I don't think so." You're still not convinced.

"I promise you'll enjoy it." You look at Crystal skeptically.

"You know you want to", Crystal adds. "Just look how hard you are."

She has a point there -- your cock has maintained its rigid state during the conversation. You are still incredibly turned on from sucking off your sisters and you have to admit you are a little curious.

"Oh, please Dougie, pretty please..." Sarah pleads with you.

"Okay, fine." You finally give in.

"Yippee!" Sarah exclaims, girlishly.

"Well if we're going to do this right, you should take off all your clothes." You sit back and lift up your legs as Crystal pulls your pants and underwear the rest of the way off. She pulls your shirt over your head and then gives you some instructions. "Now get on all fours and starting sucking off your sister to lube her up and I'll get your ass ready."

You obediently get on your hands and knees in front of Sarah and take her cock into your mouth. This is becoming familiar -- you are starting to really enjoy the feeling of girl-dick in your mouth.

"Make sure you get it nice and wet."

Crystal gets behind you and wets one of her fingers before pressing it against your asshole.

"Now just relax, Doug."

You try to do as she says and feel her finger push past your sphincter into your ass. She slowly pushes it in to her knuckle and then starts working her finger in and out. You let out a sigh, surprised at how good it feels. Sarah pushes her cock forward, prompting you to resume the blowjob Crystal’s actions has distracted you from. You feel Crystal push a second figure in your ass, then a third, thrusting in and out steadily. You moan around the cock in your mouth as her fingers press against your prostate.

"Okay, I think he's ready for you now, sis. Turn around, Doug."

You take your mouth off Sarah's cock and turn around, presenting her with your ass. She places her hands on your hips and lines up her member to your opening. You gasp as she presses forward and you feel her dick penetrate you. She forces more than half of it inside you, causing you to wince in pain.

"Gentle." Crystal rebukes her. "Let him get used to it for a minute."

Sarah obediently holds still, allowing your ass to adjust to her cock. It feels strange having something so large and hard pushed up your backside. It's a little uncomfortable, but not nearly as bad as you were afraid it would be.

"It looks like he's ready for more." Crystal informs Sarah, who starts pushing forward again. You grit your teeth as her member slowly works its way further up your colon. Finally you feel your sister's hips against your butt cheeks and know she has fully embedded herself inside you.

"Ughh" Your sister grunts. "This feels amazing -- he's so tight!" She holds still again, so you can get used to her whole length.

You can't believe your situation -- on your hands and knees, naked, having just lost your virginity to your little sister with the help of your older sister who watches on lustfully. You know you should feel ashamed, but all you feel is arousal as the pain in your ass fades, replaced by glowing warmth.

Eager to continue, Sarah pulls back so that only her tip is inside you, leaving you feeling strangely empty and then slowly pushes forward, filling you up again. You moan involuntarily as her cock rubs against your prostate. She works her way in and out of you, picking up speed as she continues to fuck you.

"Yeah, fuck him, sis! Fuck him harder!" Crystal urges her on.

Sarah picks up speed screwing you harder as her lust builds. The pleasure you're feeling is undeniable now, and you even start pressing back every time she thrusts against you, trying to get her as deep as possible. You've closed your eyes to focus on the wonderful sensations in your ass and so you haven't noticed Crystal kneeling in front of your face until you feel something soft and warm enter your mouth. Understanding her intention, your open your mouth wider, welcoming her delicious cock inside.

You're being fucked at both ends now, Sarah in your ass and Crystal down your throat, back and forth between them. All three of you are moaning as the pleasure continues to build, your sisters fucking you harder and harder. "I'm...I'm cumming!" Sarah warns you before hilting herself in your ass, holding you there as she dumps load after load of her cum deep into your bowels. You are finally driven over the edge yourself and have the strongest orgasm of your life, your jism spraying onto the floor beneath you.

Sarah pulls her softening dick out of your ass, a small stream of cum spilling out, but Crystal isn't finished with you yet. She's fucking your face furiously now, no longer concerned about your well-being, but consumed with the need to blow her load, her cock slamming all the way down your throat, her sack continually slapping against your chin.

"Here it comes..." She stops thrusting and pulls her dick back so only the head is inside. Her first squirt fills your mouth, and with nowhere else for it to go, you swallow it down before it is replaced by a second load.

"Yes, drink that cum, swallow it down!" she encourages you, as she unloads more and more of her cum in your mouth. You try to keep up, swallowing as fast as you can, but some of it escapes around her cock, dripping down your chin. Finally she finished with a sigh and you swallow the last of it down as she pulls out of your mouth.

As you come down from your sexual high, you know you she feel ashamed about what just happened, but all you feel is immense satisfaction as girl cum dribbles down your chin and out your ass. "I told you you'd enjoy it." Crystal says with a smirk, eyeing the puddle of your cum beneath you. You smile in agreement -- that was probably the most pleasurable experience of your life.