She sat on your lap

"Then sit down slowly on my lap, and we'll get started."

Nancy sat down on your knees and slid back until her ass was pressed against your meat. She rubbed up and down, forcing your cock through the crack of her ass and ripping a moan from your throat. You reached around her and squeezed her huge tits, pinching her nipples. It was her turn to groan aloud. She lifted up and grabbed your shaft, trying to locate her dripping slit. She mumbled, "Gotta have it. Gotta have you in me." She seemed a little frantic. You felt your head slip inside Nancy's slick opening. She dropped her body on you hard, and you gasped as her cunt swallowed your full length. She shrieked as your cock invaded her body. She quivered in front of you, savoring the feel of your shaft piercing her depths. "Oh, my God, Mr. Doe! Your cock is fucking awesome!"

Once she was ready, Nancy put her hands on the armrests of your chair, firmly planting her feet on the floor. She pushed herself up, making sure not to let you out of her slot. Very slowly, she lowered herself back down, groaning all the way. The tight hold her pussy had on your shaft let you feel every inch of her inner flesh. Using her arms and legs, she began rocking in the chair, pulling you out and pushing you into her slippery cunt. Every time she bottomed out with your cock fully inside her, she moaned.

You squeezed her tits in both hands, then pinched her nipples, which also got her groaning. As she fucked you, your cock tingled with excitement from her hot cunt. You slipped one hand down her belly until you arrived at her quivering mound. You searched with your fingers and found her weeping slit and pulsing clit. You ground your thumb into her clit, and she jumped and screamed at the same time. "Oh, Mr. Doe!"

You wanted a little different action now, so you stood up, with Nancy still humping you, and turned her toward the desk. She slumped on top of the papers, holding herself up with her elbows. Behind her now, you started pumping your dick into her willing pussy with a vengeance. You still have a hand on her tit and a thumb on her clit as you pound away from behind her.

Nancy was gasping and panting as you ream her pussy, shock waves traveling up her body with every impact. She lifted her head up and roared as an enormous orgasm claimed her. "Oh, my God, Mr. Doe! I'm cumming!" Her body shook with the **** of her ecstasy, and you could feel her cunt squeezing your shaft. Enough was enough, and your cock burst in a shower of hot white lava into Nancy's womb. You slammed her body toward you, penetrating as deeply as possible and held her, as you filled her with your spunk. She whimpered and squealed at the feel of your slippery sperm squirting into her. Nancy pressed her ass back into you, pumping you to get every last drop. You both were finally spent, and your cock slips from Nancy's dripping slit.

"Oh, that is so hot, Mr. Doe. I can feel your junk inside me, squishing around. If you can fuck like that, I'll be here for every detention. Maybe even an extra couple. This will be the best extra credit I've ever done for a class. Lots better than the spankings Mr. Nelson gave me last year for Biology. Unh! Shit!" Her last outburst was caused by you pinching her nipple one last time.

Nancy straightened up and turned around, pulling you into a heavy embrace. She kissed you hard with lots of tongue. You broke the kiss and began shoving your dick back in your pants. She snapped her bra and buttoned her shirt, then shifted her skirt back into place. She gave you a peck on the cheek and said, "Keep the panties as a souvenir, John." She winked and walked jauntily out of the room.