I have several sex scenes that I've collected and analyzed, so I'm going to share another. It seems that my favorite kind of sex is funny sex. Adding humor and a light moment can be another good reason to create a sex scene! (I forgot to mention on the last excerpt that the italics are mine, used to point out particular word choice.)
Excerpt from Twisted City by Jason Starr, 2004
David: main character, middle class businessman - alone in his bed, humorous, his POV, conflict within self
Angie : character he describes as perfect wife material, just met her
Rebecca: his girlfriend whom he wants to dump
Charlotte: a whore whom he just met
No need for atmospheric detail.
Language: words are surprisingly clinical, but the scene comes across as casual and graphic.
Character development and plot movement: shows lack of control and decision, his being drawn to the worst partner for him, ability to let it all go, a step toward seeing him as twisted, a major characteristic moving the plot
(After he has been imagining having sex with Angie)
Unconsciously, I had started to masturbate. I continued, pulling down my underwear for easier access, imagining that I was lying on my back and Angie was next to me, taking off her panties. Then she climbed on top of me and I slid into her. She started bouncing up and down as my hands squeezed her heavy breasts. My hand action quickened as I saw Angie’s face, and then Angie turned into Rebecca. I was getting closer and I wanted to get rid of Rebecca and see Angie again, but then Rebecca became Charlotte. I tried to think about Angie again, but Charlotte was sticking. I could see Charlotte clearly, her tiny breasts in my face. It was too late to stop, and I concentrated on Angie, seeing her again for an instant, and then there was a rapid flux. I was thinking about Angie, Charlotte, Angie, Charlotte, Rebecca, Charlotte—shit—Angie, Charlotte, Angie, Angie, Angie, Angie, then—right as I started to ejaculate—Charlotte.
Miserably, I rubbed the semen onto my leg until it had mostly absorbed. A few minutes later, I was asleep.