Why not both?

After a bit of thought, David says, "You know what? There's no reason I can't do both."

He lets go of Emma's breasts in order to unfasten his pants. Once they are open, he makes his way over to the leather armchair (Tom's armchair, Emily thought with a shudder) and pulls his pants down before sitting in it. His cock is already erect, a pale pink pole towering over a dark bush of pubic hair.

"Come over here and give me a titjob while I talk," he orders.

Emma feels herself blush as she responds, "Um, I don't think..."

"I'm not asking," David interrupts, the shy boy that first came through the door now completely gone, "I own your tits, which means I get to do whatever I want with them. And right now I want them wrapped around my dick jerking me off. So get to it, before I call the agency for a failure to comply with the terms of our contract."

Not wanting to get in trouble on her first day, Emma slowly approaches the sitting boy and drops to her knees in front of him. She lifts her boobs up and parts them enough to slip his dick in the middle of them before pressing them together with her hands. She then slowly started moving her breasts up and down the shaft, his penis head popping in and out of her cleavage like an indecisive groundhog.

"Oh yeah, that's the stuff," David says with a satisfied sigh, "You're doing a good job."

"Thanks," Emma says quietly. She didn't have much experience with giving titjobs before now, having only given Tom one twice before, so she wasn't entire sure if she was doing it the 'right' way. Then again, she doubts David does either, so as long as he's happy she decides to keep doing what she's doing for the moment.

David basks in the feeling for a minute or so, then looks down at Emma and asks, "Now first things first: your profile at the market says you're unemployed. Is that still true?"

"Y-Yes," Emma answers, "I only put my boobs on the market this morning, so everything on there is accurate."

"Wonderful," David replies, both to the statement and the heaven he was currently experiencing, "That'll makes things easy. Obviously I want to know where my tits are at all times, so you're going to inform me whenever you go out exactly where you are going and for how long, updating me if your plans change. Oh fuck yes, this is awesome..."

He takes another moment to enjoy himself, then continues, "Yeah, and I want these titties out in the open for the world to see, so from now on you're only allowed to wear tops that expose your cleavage. In fact, when you're at home or at my place, the only thing you're allowed to put over those beauties is a sexy bra. Got it?"

"Yeah, I got it," Emma said, trying her best not to flinch at the feeling of his hairs tickling the underside of her breasts as she continued using them to stroke his member.

David smiles, "Fantastic... now the contract says that you need to give me unrestricted access to your tits, so you'll need to keep the doors around your house unlocked at all times, at least the ones that the house key I got from the market doesn't work on. That goes double for the bathroom, because I want to watch you wash those sweater puppies whenever possible. In fact..."

David tenses up a bit as his dick twitches inside their pillowy domain, and Emma thinks that he's going to cum. But after a few seconds he relaxes and continues, "In fact, I don't want you washing them at all if I'm not there to see it. You can either call me or come over to my place to wash them, whichever is more convenient for me."

And there it is. Emma figured that he would bring up some odd request that would horribly inconvenience her day-to-day life at some point. But of course, he was paying good money for the right to, so Emma couldn't really argue. Instead, she nods and says, "Anything else?"

"Um, let me think..." he says, his breathing becoming heavier, "I don't... oh fuck, I can't think of anything else with these monsters around my cock."

"Want me to stop?" Emma asks, slowing down her pumping.

"No, keep going!" he says, "But go faster."

Emma obeys, moving her boobs up and down his shaft more quickly. David goes quiet at this point, not saying much other than the occasional 'too rough' or 'too slow' so she can adjust accordingly. It isn't long before he tenses up again, and this time Emma knew he'd be cumming, even before he started to say, "Fuck, I'm gonna..."

David suddenly reaches forward and grabs Emma's breasts, wrapping them tight around the top of his cock as he cums. Her breasts are large enough that the majority of his semen pools between them, but the head of his dick sticks out just enough to shoot some jizz across the top of her boobs, and one shot even hits her chin. Once he's done, David relaxes in the chair, thoroughly spend.

"Damn, that was... great!" he says, a big grin on his face.

"I'm glad you liked it," Emma said, wiping the errant cum off her chin with her thumb before standing up, "I'll be right back."

"Where are you going?" David asks her.

"To the bathroom. I need to wash..." Emma starts, before remembering what David told her, "Um, I mean, can I wash your... uh, stuff... off of my..."

"Not right now," David says, his cock rapidly deflating. Shortly after he asks, "You have a boyfriend, right?"

"Um, fiance, actually," Emma corrects, "We're getting married in a couple of months. I guess I have you to thank for that, actually... the money for my breasts is going to the wedding."

"Really?" he asks, seeming to go back to his awkward teenager mode for a moment, "That's... actually pretty sweet of you. He's pretty lucky."

"Yeah, he is..." Emma says, "And so am I."

"Do you two live together?" he asks.

"Y-Yes..." Emma says, suddenly getting a sinking feeling in her chest.

"Okay, well I'll probably meet him at some point then," David says, "If he's cool, maybe I'll even let him play with my tits on occasion. Which reminds me, no one other than you or me is to touch those babies without my permission, especially him."

"Of course," Emma says with a frown. This wasn't unexpected, of course, Tom even told her it might happen, but it still felt weird to be ordered that all the same.

David suddenly got a wicked smile on his face as he looked at Emma's cum-stained tits, "Actually, when's he coming home?"

Emma checks the time on her phone and answers, "A little over an hour. Why?"

"That's reasonable enough, I think," he says, standing and pulling his pants back up, "Leave my cum where it is on those titties. I want your fiance to really see that another man owns them for the next three months. Oh, speaking of, stick them out for me for a second, will you?"

Emma obliges, and David pulls out his own phone and snaps a picture of them, "There we go... I want to remember this day forever."

Emma winces at this. She isn't entirely sure if she can put up with this kid for three months. Not to mention how Tom's going to react when he sees... this. She idly wonders if David will stick around to watch that moment, or get bored and leave Emma to deal with it herself.