Try something small

"So..." you said slowly, weighing your options, "would you mind paying me back by sitting in my lap? I kinda like to cuddle after... y'know."

"Of course you do," Cara smirked, but stood up and walked to your side of the booth anyway. She pushed the table away from you a bit to make room, then draped herself along the seat. She wiggled her butt against you a bit to get comfortable, her slender legs folded to one side and her arms holding onto your neck. You support her back with one arm and lay the other across her thighs, taking the opportunity to investigate her curves.

"Watch the hands," she joked. "Jacob gets very jealous."

"Oh, I know..."

The first time you'd met Jacob, he'd "caught" you and Cara chatting between classes. He'd literally pulled you out of your chair, and very nearly broke your nose before she could explain that you were just an old friend from high school. Even then, he barely let her see you when he wasn't around.

"What do you think he'd do if he caught us like this?" you asked, suddenly a little scared.

Cara was genuinely confused; "Like what? I'm just returning an innocent favor. It's not like you just let me suck you off! By the way..."

She glanced around surreptitiously before leaning in and whispering "Did you see the tits on that woman? I can't imagine what she must spend on bras!"

"Probably not much," you laugh. "Her nipples were about to poke holes in that uniform."

"Before or after your special order? I think she likes you! What I wouldn't do to get my lips on those things... Shit, here she comes! Act natural."

You act as natural as you can with your bisexual best friend on top of you as Gabrielle comes back with the check. Her nipples -- which you do not look at -- are as perky as ever. Her "tip me" smile gains some genuine warmth when she sees you two all intertwined.

"Another favor?" she asked. "Aren't you Mr. Selfless!"

"I'm doing this for him, actually," Cara explained with something like pride, "to pay him back for letting my practice on him."

"Well," the waitress laid your check on the table, "you two come back anytime, and you ask for Gabbie. I always take care of my favorite customers, y'hear?"

She turned to go, but you stopped her. Something Cara said had given you an idea.