Blow his mind.

Beth said nothing, only watched in fascination while rubbing her pussy as Seth dug out his cock. It stood at attention, pinned to his body by the tight band, with the balls remaining concealed beneath his briefs.
"Hmm...." Beth put a finger to her lips. "Not bad." It wasn't bad. He was definitely at least equal to Brian. Don't think about Brian right now. Just give him a little fun and get out.
"So... what are you going to do to help me...help you?" Beth had taken some of the power back in the situation, but his tone told her that she had not taken all of it. To get what she wanted, she was going to have to work. Alright then... Beth slid gracefully to the floor between Seth's legs, taking hold of his cock with both hands while he brushed hair back from her face. Beth thought flettingly about a hair tie from her purse, but it was not in arm's reach, and Seth's cock was beginning to beckon her, this close. I really still am a slut for a nice dick.

Beth got to work on the blowjob without much ceremony, with her initial intention being to get it over with quickly. Seth was sweaty and stunk a little, but he was clean and his pubic hair wasn't wild and unruly like many guys. All in all, she began to relax into the activity, losing herself in the pure tactile and mechanical pleasure of sucking dick.
"That's good, baby. I like a girl who knows how to get what she wants..." Seth kept her hair back from her face: he seemed to want to see his cock go in and out of her mouth, and for Beth's part, she couldn't avoid flashing him some eye contact and a smile.
Even after slowing down and savoring the activity, it didn't take very long before Seth announced his need to blow. Beth pulled out the stops, deepthroating and **** herself while rubbing his balls until his sticky payload began to pour onto her tongue and paint the insides of more mouth. Once he was done spurting, she pulled the remainder of his cum out with a long slow suck combined with a squeezing of her fingers along his shaft. A quick swallow disposed of the evidence, and she smiled.
"There... so you'll remember our agreement, right?"
"Absolutely..." Seth looked smug and satiated, leaning back and clasping his hands behind his head. "I'll give you all the help I can..." he had a glint in his eyes, though. A glint that suggested to Beth that this wasn't a simple exchange. she wasn't sure how to feel about that as she dressed and excused herself from the room. Mixed feelings pursued her to her car, and as she drove home, she wrestled with herself. On the one hand, she had needed his help to smooth things along towards this new opportunity. On the other, she had certainly put up no resistance to the idea of blowing Seth to get what she wanted. Had she been secretly hoping things would go this way? Was she...intrigued for more? She tried to suppress those worrying thoughts. It was a one time thing. This is no time to regress back into a full blown slut.