She leaves them off

Instead of hearing the flick of a lightswitch, you feel a hand on your crotch! You nearly drop the bag of groceries from the surprise.

"Don't worry, hon'." She says. You can tell by the direction of her voice that she is on her knees in front of you.

You start to breathe heavily as she unzips your pants and pulls them down. You hear a little gasp from her as she feels your cock through your boxers. You've got a raging hard-on like you have never had before. She slides her hand up the right side of your boxers and starts to massage the base of your cock and with her other hand squeeze your balls. Instead of taking your boxers off, she licks the tip of your dick through them. You nearly blew your load right there, but she stopped just in the nick of time.

"She must have a lot of experience to know when a guy is about to cum." you think to yourself. You begin to wonder how many cocks she has sucked when she nearly rips off your boxers. Since she hasn't turned on the light you ask if she can take the bag and put it somewhere where it won't fall over. She doesn't say anything and starts to lick up and down your cock. That is when you hear a loud thump behind you.