When I first started writing Bryony, I read a post about how editors often cringe at sex scenes beause so many of them are so badly written.
For many writers, writing romantic/sexual tension is difficult for two reasons: we're embarrassed, and we focus on "the deed."
However, despite the many variations one can find in books and online, "the deed" is still fairly universal and straightforward, despite the temptation to purple-prose it up with really awful mataphors. However, the thoughts, feelings, responses, and value judgments of the characters involved, well, these are as indivudual as the characters.
Building good tension takes time, more than even the excerpts here, but these are offered merely to get your creative juices flowing (cliche, pun intended). Elements of that tension may include past frustration, longing, anticipation, and knowing your audience. The particular details of tension in a young adult book is different from one that is triple x, but the foundational feelings are the same.
John wrapped his arms around Melissa, and all her trepidation melted. He felt so strong, so solid, so protecting. Was this magical moment part of his covenant to her? It was beyond her wildest dreams. How could she ever have mistrusted him? She looked up at John and saw he waited for her answer. Why would a man this talented and wonderful look at her in that way? His face moved closer to hers, and his lips were very near. ("Bryony," Chapter 12: A Fair Trade)
John admitted he had not, but his tone was flat, and Melissa wondered if he had really heard her. The more Melissa talked, the less John heeded her words. Several times, John’s eyes drifted away from Melissa’s face and roamed the rest of her in a manner that caught her breath and halted her speech. His smiles grew less bright and more distracted. Finally, Melissa’s voice trailed into nothingness. John brought forth his watch, noted the time, and repacked the remains. Melissa bit her lip, but what could she do?
Instead of lugging the basket to the boat, John pushed it to the edge of the blanket. With a brief stretch, John lay down, looked at Melissa, and patted a spot on the blanket next to him. His face appeared tranquil, but his eyes held a yearning, almost hungry, look that nearly smothered her. This was it. She couldn’t refuse him now.
Fairly bursting with happiness, Melissa inched away from her place on the blanket and lay next to him. John covered her hand with his, but he did not speak or glance at her. Neither one moved, but every so often, John’s fingertips caressed her skin. They lay there in silence, watching the shadows of the trees lengthen, and the sun dip lower in the sky, exploding into vibrant reds, yellows, and oranges. Gradually, night settled over Lake Munson, and the brilliant colors darkened into purples and blues, but still Melissa felt no urge to leave for Simons Mansion. She only wished this moment would last forever because, although John still did not talk, neither did he release her hand. Feeling more serene than she had in a long time, Melissa closed her eyes and allowed the approaching night to wrap her into its comforting cocoon. She was afraid to respond; she was unwilling to break its magic. Instead, Melissa listened to the lake dashing itself against the shore. She heard the distant call of an unknown bird. John’s breathing sounded steady and rhythmical. She wondered if he had fallen asleep.
Without warning, John’s fingers traveled up her arm, past her shoulder, and to her neck. They stopped at the base of her throat and rested there, warm, unmoving. Melissa melted into his touch, unable to tell where she began, and his fingers ended. ("Bryony," Chapter 24: It's No Use)
Head held high, Melissa strutted out the door and toward the stairs. However, as she drew close to the security entrance, Melissa’s legs began shaking so hard, she curled her toes to keep from buckling. She stumbled to the door with as much dignity as she could muster and willed her chattering teeth to be still. The security guard, an upperclassman with several textbooks spread out before him, didn’t notice Melissa’s distress. Melissa glanced at her watch. Ten minutes to go. She leaned against the wall and ordered her racing heart to behave. Tonight, Melissa would have no rehearsed Bryony script to guide her. What would she say? How should she act? She checked her watch again. Nine minutes to go! She half-expected to see Henry in a three-piece midnight blue suit stroll through the door, apologize for the professor’s tardiness, and then announce he was the substitute date for the night. Oh, what was taking Johnny so long? ("Visage," Chapter 4: Outdated)
Suppressing a sigh, Melissa reached for the door handle, but John, with a quick dart of his eyes, leaned his hand across the back of her seat and locked the door. Melissa held her breath, but the pounding in her ears was deafening. Melissa closed her eyes, and time stopped.
She heard a click, then a creak, and her eyes flew open. John had unlocked Melissa’s door and was now offering his hand. John grew blurry against tears of disappointment. Do not cry, Melissa told herself.
“Thanks,” she mumbled, forcing a cheerful smile while taking his hand, reveling in the warmth of his fingers and trying to act unruffled by the contact. She failed.
“Say ‘hello’ when you pass me.”
Melissa paused. Again, nothing happened. As she started toward the cafeteria door, John gently caught her wrist. She stopped. Heart racing, she turned to look at him. He slowly moved his eyes along her face and farther down, then back up again. It was how John had looked at her the night of orientation; it was the way he had gazed at Bryony when he lifted her veil. Melissa could not breathe.
("Visage," Chapter 4: Outdated)
All day Monday, Melissa harnessed her will power and focused unwaveringly on her schoolwork. That night at closing time, as Melissa checked out a stack of books, Johnny Simotes walked through the front door. Melissa immediately dropped to the floor and pretended to search for something on the bottom shelf.
She counted to ten, stood up, and breathed a sigh of relief. The professor was gone. The student at the counter looked aghast at her queer behavior, grabbed his books, and nearly sprinted out the door.
Pat something, a tall, friendly girl with short brown layered hair, arranged books on a nearby cart for shelving. As she slid a stack off the counter to give to Pat, Melissa caught sight of Johnny walking to the desk with two books in his hand. Melissa spun around and quickly joined Pat.
“Um, I’ll handle these,” Melissa said in a low voice. “Why don’t you wait on him? You’ve been stuck doing this all night.”
Pat shrugged. “It doesn’t matter to me.” But she approached the professor just the same.
Melissa turned her back to counter and very slowly added her books to the cart. Johnny said something in tones so muted, Melissa only heard the sound of his voice.
“She’s busy at the moment,” Pat said.
Pat returned to the cart. “He’s asking for you.”
Melissa’s face burned. She glanced up. Mr. Schmidt was observing the exchange and frowning. He preached, and monitored for, sterling customer service, especially when the customer was a teacher. Melissa felt stuck. She had no option but to face the professor. Great.
She returned to the front desk, gave Johnny a polite, “Good evening,” and rapidly stamped his cards. Melissa noticed both books pertained to advanced music theory.
As Melissa slid a due date slip into the front pocket of the second book, Johnny placed his hand on hers. A flushing warmth flowed through her at his touch. All thought froze; every heartbeat hammered out a single syllable, John. Melissa forgot about Mr. Schmidt, Pat, the cartful of books, and her promises to forsake the Bryony fantasies. Nothing else mattered. John had made contact with her.
("Visage," Chapter 3: In The Shadow of Bryony)