"Please don't!" Reta screamed. Her intense high-pitched tone rang throughout the cave and vanished as fast as it came.

At once, Iris stopped her playful banter with Dulcie and jumped out of the pond. As fast as possible, she rushed out of the room and towards the entrance of the cave. Though she was faster than before, she was still slower than Dulcie, who took her hand and dragged her along.

In the moment of heightened concentration, Iris spread her perception in all directions. She mapped out the cave by listening to the echoes and feeling the airflow. Her weak, melting body took a defined shape as she needed it to quicken her pace. Her hair spread under the wind into countless threads as if she momentarily returned to her humanity. Though she didn't know it, Dulcie almost pushed her away due to her human-like touch.

At the entrance, sunlight illuminated the shade and highlighted two Monster Girls. A Snake Lady coiled around Reta, licking her face and groping her body. She gently hissed and watched Reta suppressing her moans. Only until a cute voice leaked out did she shifted her attention to the newcomers.

Dulcie took a deep breath. She pulled Iris closer and slowly retreated to the cave. Her body tensed, trembling nervously.

"Little Dulcie, why are you going back in?" the Snake Lady, Vilia, said. She then shifted her attention to Iris. "A new Monster Girl? I'm Vilia, your friendly Snake Lady from a cave nearby."

"Iris, don't let her get to you. She is one nasty Monster Girl." Dulcie glanced at Reta, who silently cried in her ill fate, and shook her head. "We must go. Only Sister Lenmia could subdue her."

"Leaving already? Come here, Girls."

Vilia pointed at Dulcie. The soil beneath her grew green. Stale water seeped through the dirt, sinking it into a marsh. The viscous ground pulled Dulcie and Iris groundwards. The moss which grew from magic sprung upwards. Its tendrils bound Dulcie but failed to obstruct Iris's naturally slippery slime body.

Dulcie wiggled the flower on her head. It exuded a soothing fragrance and spores. They fell onto the surrounding, which turned everything weak and lazy. The moss loosened their grips. In a split second, Dulcie pushed Iris away and swung her vines at Vilia.

Vilia, smiling, stooped down and slithered close to the ground, holding onto Reta while dodging the vines. She rushed to Dulcie and caught her arms. Her tail quickly coiled around Dulcie and squeezed her with Reta.

"I haven’t had a three-way fun for a while now, so please endure until I'm satisfied," Vilia said while moving her slippery hands and tongue across Dulcie and Reta. The suppressed moans leaked and permeated the atmosphere with a clandestine vibe.

"No, don't," Dulcie muttered as she saw Iris trying to help her. "Leave now, Iris."

Iris, who reformed her body a distance away from Vilia, averted her gaze from the scene. Her eyes moved between the cave and Vilia. She couldn't go against her, but she couldn't leave her sisters in danger either.

Vilia's long, slithery tongue and her sisters' helpless appearances forced her to make up her mind. She had already been violated once. More wouldn't make any difference. She accepted her fate and manifested blobs of slime out from her membrane.

"Hang in there, Sis!" she said and flung her arm. Drops of sticky slime flew towards Vilia, who easily avoided them.

She slipped through the gaps between them. Though some of them landed on her body, her speed remained faster than Iris anticipated. She rushed in and reached out. Iris jumped backwards, but she was slower than Vilia.

From the cave, Tardi tensely raised her hands upwards. The ground in front of Iris creaked and shot skywards into a small pillar of dirt. Vilia crashed against the soil and went through it, though she also passed through Iris's melting body.

The slime coated Vilia, making her body more slippery than before. Her restraints around Dulcie and Reta loosened as both struggled. Dulcie ordered her flower and vines to move, creating frictions and titillating Vilia.

"Wait, if you do that with the slime—" Vilia's cry cut her speech short. She tumbled against the ground and rolled. Her purple scales turned reflective and sensitive from the slime.

"Reta, do it," Dulcie shouted and grabbed onto Vilia. Her vines wrapped around the lower snake body, rooting it against the ground. Reta reached out for Vilia's soft, pale neck and bit onto it with her fangs. Purple blood bled out of the wound while transparent venom seeped into it.

As the venom spread across her body, Vilia's struggle weakened. Her body heated up as she stopped rolling and focused on coiling around herself, planting her face against her scaled body. Her hand gripped the bite mark on her neck. It filled her neck and cheeks with pinkish warmth.

"You guys got a lot better at fighting," she muttered while staring at Iris. "I didn't know Lenmia has gotten a new member into her family. Sister, may I know your name?"

"Iris. Why did you attack us? We haven't done anything to anyone."

"Attack? I see. You're still pure, maybe too pure." Vilia smiled. "You did this, Reta, but I think I want to taste Iris more."

The ground shook and depressed like quicksand. Stale water flooded the soil into a dark green swamp. Bubbles and moss filled the grasses and rocks, tainting the vibrant colours with its dull, darkened grey. The fresh air turned fouled, polluted by toxic gases which poisoned everything with confusing exhilaration.

Reta inhaled the air and collapsed against the ground. The mosses crept onto her. She cried for help as sleeping gas choked her lungs until she ceased her struggle. She slowly sunk into the swamp while the sweats and oily water coated her body.

Dulcie closed the flower on her head and held her breathes, but the filthy ivies rooted her in the marsh. In front of her, Vilia overwhelmed the venom and swung her tail. It knocked Dulcie against the soft soil which sank and imprisoned her.

"Now, Iris, this is an attack, not a teasing like before," Vilia said while caressing her shoulders, trembling at the touch. "No one can interrupt us now."

Iris struggled to move. Her slimy body froze in the thick air of the swamp, which prevented her from dissolving and moving in the liquid puddle form. Despite how her body began to heat up from the poisonous gas, she refused to yield to any temptation.

Behind her, Tardi channelled her power. She attempted to control the ground by raising her hands, but Vilia was more powerful than her. In the end, the marsh seeped through the dirt and caught her feet. It dragged her muddy body downwards and dissolved it under the water.

Only Iris and Vilia were left standing.

"No help now, Dear," Vilia said. "Don't worry, they'll get to enjoy your pleasure too, after I've tasted you."

"If you want me, then just do me. Leave them alone," Iris said and feinted a smile. "I don't think you can handle me."

Vilia giggled then leant towards Iris. Her long tongue peeked out of her lips and moisturised them. She licked Iris's neck, bit onto it, and coiled around her, soaking in the slimy, melting heat. Her hands slid across the smooth skin and caressed the breasts, groped them, then moved down to the abdomen.

Iris suppressed her weep, which leaked out like a rabbit bitten by a wolf, though the bite was playful and exciting. Vilia’s body heat transferred to Iris, boiling her mind into a mess. She melted and reformed, coating Vilia with her slime. Suddenly their lips met and their tongues exchanged. The sweetness of their saliva permeated their souls.

Vilia tightened her grasp and leant forwards. She passed through Iris’s body and landed on the soft marsh, turning back only for Iris to get on top. She sat on Vilia's abdomen, leaning towards her with hands restraining her movement.

"You're even sweeter than nectar, Dear," Vilia said. Though she could easily break away, she enjoyed switching role once in a while. "If you want me to surrender, make me."

Iris exhaled. Though she didn't need to breathe, her Monster Girl's instinct told her to do so. Her foggy hot breath diffused into Vilia, who closed her eyes and leant ahead, waiting for the play.

Iris turned red but didn't betray her acting. She stroked Vilia's body with her hands and left a trail of slime all over her scales. They smeared her body with warmth and sticky sensation, filling her with anticipation of the finishing moment. Vilia trembled from the urge to take the initiative, but she had to be patient. She would lose the reward if she didn’t stick to the role until the end.

"Got you," Iris said and closed her eyes. She fell on Vilia and placed her mouth against the moist lips. She caught the snake body in her grip and willed the slime which coated Vilia to move. They wiggled and contracted and expanded, sending itchy sparks throughout the body. Vilia panicked and pushed Iris away, but the stickiness of the slime was beyond her anticipation. She tried to breathe, but Iris's tongue ravaged her mouth and filled her throat with slimes.

Her body squirmed to get rid of the slime, though Iris had inserted them in between the scales, which stirred the sensitive flesh every time Vilia moved. Soon the sweet nectar drowned Vilia's mind, filling her thought with the desire to ravish at the moment, finally stopping her escape and beginning her assault.

She pierced her slithery tongue out and dove it into Iris's body. It wiggled around every part of her translucent body, poking in and out while savouring the sweetness. The tickles excited her beyond reason. Her swaying arms grabbed onto Iris and held tight, putting her closer, merging into one.

Iris, red as love, pulled herself from the crazed Vilia. She pushed her away, but she greatly underestimated how strong a Monster Girl in heat could be. Vilia effortlessly pulled her back in and slid her fingers into her body, messing her up from the inside. Passion numbed her senses. Her mind melted and refused to listen to her shame.

"Why did it end up like this?" Iris whimpered before her moans interrupted her thought.

"Dear, you make me into this, so you must take responsibility," Vilia said. "Don't worry, I'll take good care of you. No one can interrupt us now."

From the edgy of the forest, Lenmia dashed out and spread her power outwards. The bright yellow light overwhelmed the magical swamp and regressed it back to the ordinary landscape. The sudden flash pulled Vilia from her episode. She had lost track of time and forgot to account for Lenmia’s arrival.

"Really, Vilia? Don't you think you've gone too far?" Lenmia said with a solemn expression on her face. Balls of light emerged from her slime body and spun towards Vilia. They violently erupted into fireballs.

Vilia pushed Iris away and coiled around herself. Her surrounding rose into a mini plateau, tanking the fireballs. The heat melted the dirt and left a small crater of charred stones on the ground.

"Wait, Sis Lenmia, I can explain!" Vilia shouted and jumped towards Iris. "I was just playing around and—"

A ray of light descended from the sky and engulfed her vision. She shut her eyes and pressed against Iris, pulling her closer to her chest.

Iris tensed her body, tightening her grasp on Vilia. The intimacy of their bodies filled Iris with a strange warmth. Everything was going to be fine. She stuck close to the Vilia, immersing herself under the alluring security.

The ray of light broke into multiple stripes which stabbed the ground around Vilia. The searing noises of the boiling energy screeched, faintly echoing the anger Lenmia radiated. She slowly walked towards Vilia, who ducked on the ground with an exhausted yet smug grin.

"I didn't remember inviting you here, Vilia," Lenmia said and crossed her arms. "If anything happens to my Iris, I'll break you."

GDLiZy

A Snake Girl entered the fray! Totally not a self-insert!