Saved by the lube.

"Ch...check the top drawer of her...dresser..." she points. "She keeps her sex toys in there."
As you go over to check, you ask in a stern voice. "And how do you know that, Riley?" You pull the drawer. "Do you snoop around your friends stuff when she's not around?"
"Yes, daddy." she confesses.
You come back with a half-full, smallish bottle of Astroglide. "That's very disrespectful, Riley."
You flip her onto her stomach, spreading her cheeks and pouring a line of lube onto her enticing butt hole.
"More disrespectful than fucking your daughter on her friend's bed, daddy?" Riley looks back at you, a mocking expression on her face.
"What the fuck did you just say to me, Riley?" You grab a fistful of her hair, wrenching her head back until she whimpers in pain. "Are you sassing me, baby girl?" You press your cock head into her lubed knot. "You're going to be sorry for sassing me, Riley...." you push in savagely, and Riley's mouth opens wide in a pained squeal.
"aaaaaaaaaaaaaaaaaaaaaa..............." the lube helps you slide in after a few seconds of resistance. Once inside, you revel in the tight embrace of her rear hole.
"Apologize for sassing your father, Riley Marie..." You pull on her hair, and she whines.
"I'm sorry daddy..."
"If you want to be a smart ass, I'm gonna make your ass smart...." no your best wordplay, but with your cock sliding further into her hole, Riley's got other things to occupy her mind.
"Aowwwwoooooo!!!!" Riley pants, eyes pinched in pain. "You're so big....daddy it hurts...it hurts a lot!!!!" she reaches back to pull her cheeks apart, desperately trying to make more room for you.
"Sometimes..." you start to pump. "We need to endure a little discomfort or pain to grow as a person, baby..."
You proceed to ream her asshole with the help of copious amounts of lube. Riley's going to have to explain the puddle of it to her friend. Minutes of insistent work yield results: you finally push the final inch, slapping your balls against her cunt as she wails. Her face is flat on the bed and the pillow is firmly between her teeth.
"This is what you wanted, wasn't it, Riley?" You pump at a steady cadence, no longer tugging her hair, now just gripping the back of her neck. "This is what you asked for when you decided to seduce Daddy."
"Ah ah ah nn nn nn nn nn nn...." Riley's incoherent: her eyes are glazed and unfocused.

"Riley..." you lightly slap her cheek.
"NNN!!!" she whines. Her eyes blaze as she looks back at you.
"How does it feel baby? Do you like daddy's cock in your ass?"
"It....it still hurts daddy...but...." she bites her lip, then continues..." it feels good, too...."
"Okay..."
You pull free of her ass, picking her haunches up higher and kneeling down to put your face in her cunt. "You've been a good girl for daddy. Time for a reward." You eat her snatch as she moans with grateful pleasure.
"You're so good to me daddy...I'm such a lucky girl..." she whines and moans with satisfaction as you attack her clit and spear into her pussy with your tongue, while working her asshole with a finger. Before long, she's cumming: drumming her feet on the mattress as you lap at her nub. Then you push her hips down flat to the bed and re-enter her ass.
"Yes....fuck me daddy...."
You don't last 20 seconds before you burst, spraying your load onto her back and buttcheeks.
"Come here and clean up the mess you made, Riley..." She crawls around, taking you cock in her mouth and cleaning it off, reveling in the taste of her own ass.
"What a good girl, Riley." You stroke her hair.
"Thank you, daddy. Did I do well?" She looks up at you so adorably. It's so fucked up.
"Yes, baby." You lean down and kiss her gently, then sit on the bed and take her into your arms, holding her close and stroking her skin gently.
You clean up after yourselves, and Riley offers to change the sheets on Leah's bed.
"I'll see you at home, Daddy."
"Yeah..." Now that you're coming down from the high of sex, guilt is creeping back in.
You head home, and roll into the driveway around 2:15 PM.