Come up behind her

I walk into the bathroom and step up behind Cynthia. My crotch presses against her butt and I reach around her to grope her tits through her bra.

"Joshua," Cynthia says with a tone like that of someone scolding an annoying child, "I need to finish getting ready." I press myself harder against her and feel the heat emanating from her crotch through my pants.

"I'm not stopping you," I say and slide a hand into one cup of her bra, pinching the stiff nipple I find there between two fingers. "Yet." I chuckle and Cynthia rolls her eyes as she continues to try and apply her makeup. "Does your boyfriend know he's a cuck?"

"What are you talking about?" Cynthia says, glancing at me through the mirror. In my pants, my dick has grown erect, straining against the fabric and pressing into Cynthia's butt.

"We've been fucking since before you and that boyfriend of yours started seeing each other. He's been a cuck your entire relationship. Does he even fuck you?" Cynthia stops and looks at me through the mirror for a second. After a moment she begins to move her butt against my crotch, grinding her butt on my dick.

"No. We haven't had sex, yet," Cynthia says. I smirk.

"He probably can't. If he hasn't made a move now, he's either gay or impotent." I chuckle at my own words and grab at my crotch. "In any case, he can't satisfy you like I can. No one can, can they?" I reach down and readjust my cock, the tip poking out of the top of my pants.

I've had enough of this foreplay and apparently so has Cynthia. "Are you going to fuck me?" she asks, shaking her butt against me.