Barbaria, do you think you could appreciate a cunni scene ? Even lesbian ?
Here's my try to do as a male....probably females write better ?
"There was a smile on her face, fragile at first at this recollection of her youth, then warm, turning to Keiko, the young novice she was in charge of catechising. Her friendship for the young Chinese girl orphan with the opal forehead had turned insidiously into something more sensual, something she that had already been experiencing for two years already - in a platonic way - with her best friend, ever watched as they were in the oppressive enclosed life imposed by the discipline of the sisters.
Today, she felt free from all these taboos, a dizzying disruption provoked by a feeling of power and freedom had seized her.
Keiko's puzzled look at the top of her thighs irritated her for a moment. Without emotion, she her big, thick, dark bush, which only thinned out just her navel, with the barely pubescent fuzz of her new friend.
She crossed her legs and continued reading aloud. From the "infernal cupboard" of the library of the Oratorian Brothers in Juilly, in Seine et Marne, she had helped herself to the Handbook of Behaviour for Little Girls by Pierre Louÿs, before her departure for this Mission in distant China.
She resumed the verse, humming:
“I don't like how Alice when she's on heat lifts up her lingerie,
Showing her dark red, hardened clitoris, ”
Without her realising it, her hand had landed on Keiko's thigh.
The beige linen tunic had been yawning open for a long time, and it seemed to Mademoiselle Sentis that the long tips of the small but very well-formed breasts were protruding ever more under the blouse.
Keiko set her forehead tenderly on the top of Martine Sentis' thigh, chasing away a butterfly that was gorging on her friend's pearls of perspiration.
Mademoiselle Sentis gently stroked the long braid that had curled over her thighs. She resisted the urge to tighten it between her legs as if it were something else, that thing about which the maidservants of the Mission talked with giggles, and of which she had even seen drawings that made her blush and tremble all at once.
She continued her chant:
“Long as a dog’s prick, straight as a monkey’s,
And sighs - Ah my dirty dyke! Give us a lick here! ”
She felt Keiko's hand slip slowly drop down her thigh, and a sharp contraction siezing her. Keiko straightened up, vaguely frightened and ashamed, but Martine reassured her in a soft breath, placing a finger on her own mouth. She took the back of her neck in the palm of her hand and slowly brought their faces closer.
They gazed at each other for a long time, making sure to engrave on their memories this moment of perfect, forbidden happiness, far from the world. Their virgin lips clumsily sought each other for a few moments then swiftly traversed their burning bodies, swept by brief but intense convulsions. Their hands sank into the tips of their young breasts hardened by the caress of their hair.
At the same time, they found their flesh buds erect, but Keiko had to use her fingers to keep the access to the very musky-tasting flower at the tip of her tongue clear. Mademoiselle Sentis, on the other hand, could wander freely around her large, fruit-fresh lips, so delicate that she would have liked to bite them, barely adorned with a few long, smooth hairs, through which her own tongue slipped without difficulty.
They patrolled through their intimate parts with their fingers, their noses, their tongues, with all the frenzy of hungry young bodies before coming together, their sinews harmoniously plucked in an echo of their own pleasure. Then they rested, exhausted, lying side by side, hands trembling, hands that still sought one another. The awakening breeze beneath the leaves of the great mangrove tree did not cool their oozing skins. After a few moments, they straightened up at the same time, and kissed, stroking one another's hair. They fell back again, determined to take their time to soak up their feminine scents, to dart their tongues into each other's narrow slit, and - supreme audacity - to push their fingers into all their orifices at the same time."
I always like to start like that, and... reduce my tension before session. 
And long or short? Depends on the stroy and how you describe. Just make it hot 
