Train her throat.

"If you're going to please Daddy, we need to train your throat..." you flip her over on to her back, and pull her closer until her head hangs off the bed. Her eyes are watery and a little bit apprehensive.
"...I want to please you, Daddy..." she sniffles a little, "but, I'm scared. You're so big..." You stroke her cheek.
"Open wide, Riley." Your tone is gentle but firm, letting her know there's no arguing.
She nods, and lays her head back and opens wide.

You plunge your cock into the waiting hole, squeezing her tits and pinching the nipples as you work your way into her spasming throat.
"Hrk...hrk.....hrk!!!" Riley's hands start flailing, and you catch them, holding them against her stomach. "Relax, baby girl." She calms a little, and you continue to work her throat, inducing her gag reflex and letting off. Spit and mucus are starting to run in rivers down her face, over her closed eyes and into her hanging hair. Snot leaks from her nostrils as she tries to breathe.
"Nnnnnn!!!!" She's moaning and whimpering, **** around your cock. You reach up to finger her clit, at the same time leveraging more of your weight against her, really pressing your cock deeper into that throat. "Come on, Riley. I want that nose on my balls, baby. You can do it."
Riley's hands flash out to grip your hips, and you grumble. "Riley..." but then, you realize she's not trying to push you away. She's gripping your ass, pulling you closer, fighting to get her nose into your ballsack.
"Oh, good girl. Such a good girl!" You praise her as you feel the tip of her nose rubbing against your balls. You pull back, letting her spit and cough and snot as she gasps for breath. Her face is a mess of fluids, mascara and foundation smearing and dripping onto the carpet.
"Did..." her voice is froggy, and she rubs at her ruined throat. "Did I do a good job, Daddy?"
"So good baby. And here's your reward." You climb on top of her lithe, sexy body, laying you wet cock against her entrance as she stares up at you, a little dazed. "Are you ready?"
She nods. "Yes, daddy. Please give me your cock?"
For the next few minutes, nothing can be heard over the sounds of Riley's yelps and moans. "Oh..Daddy...Oh daddy...its so thick...i love it....fuck me!!" Her snatch is unreal. So tight, so warm, gripping and yielding by turns, wet and slippery and incredible.
"Do..I.. Feel...good....Daddy?" She asks as you pound her pussy.
"Amazing, baby girl. Daddy's going to blow soon." You are. It's already building.