Yes, he tries to paint her backside, but is too clumbsy

"Right, the back," Robin said, his voice cracking. He adjusted his glasses, which had slid down his nose from the sweat beading on his forehead. "Just... grab your ankles, Soph. I need to get the gluteal contour."

Sofie let out a long, shuddering breath. "If you say 'gluteal contour' one more time, I'm going to scream." Nevertheless, she bent forward, reaching down to grasp her ankles. The position left her completely ****, her backside thrust up and out, her legs spread in a wide, unbalanced stance.

"Steady," Robin said, placing a hand on the small of her back to stabilize her. The contact was electric. Sophie’s skin was hot to the touch, and she tensed under his palm. "I'm just... balancing you."

"Uh huh," Viki chimed in, sitting cross-legged on the floor nearby to get a front-row view of Sofie’s predicament. "Make sure you get the underside, Robin. Real shorts ride up, remember? Don't leave the bottom of her cheeks unpainted."

Robin dipped the sponge again. He moved behind Sofie, confronted with the sight of her upturned bottom. He swallowed hard. "Okay. Here we go."

He slapped the sponge against her right buttock. The cold paint made Sofie yelp, her hips jerking forward.

"Sorry!" Robin squeaked. He gripped her hip tighter with his free hand to hold her still. "It's just cold."

He began to rub the sponge in large, circular motions, covering the round globe of her ass. The friction of the sponge against her skin, combined with the heat of Robin’s hand gripping her waist, was sending confusing signals through Sophie’s body. She felt exposed, humiliated, and oddly... tingly.

"Get the crack," Viki ordered unhelpfully. "It needs to look like the fabric is wedged in there a little. Realism, Robin!"

"I'm getting there!" Robin snapped. He dipped a thin brush into the darker shadow paint. He leaned in close, his face inches from Sofie’s rear. With a trembling hand, he brought the brush to the cleft of her ass.

Sofie gasped as she felt the bristles tracing the line of her bottom cleavage. Robin had to use his other hand to part her cheeks slightly to get the line right. "Robin! No!"

"I have to see the line!" Robin insisted, his fingers sinking into the soft flesh of her bottom, pulling her open. "The shadow has to be precise!"

He ran the brush down the crease, the tip tickling the sensitive skin she had never touched herself. The sensation was overwhelming. Sofie’s legs began to shake violently, her muscles clenching near Robin’s invading fingers.

"Whoa, easy," Robin said, feeling her squirm against his fingers. "Don't smear the paint."

"Can't... help it," Sofie panted, her face burning. "It tickles... it feels... weird."

"Tickles?" Viki laughed. "She looks like she's about to cum, Robin. Check the front again."

"I'm not checking the front!" Robin retorted, but he couldn't help himself. His eyes drifted down between Sophie’s legs, which were still spread wide. From this angle, he could see the painted blue lips of her pussy, and beneath that, a glistening trail of fluid starting to leak out.

"Uh oh," Robin said, freezing. "We have a... breach."

"Again?!" Sofie cried out, trying to stand up, but Robin’s hand on her back held her in place. "Let me up! I need to wipe it!"

"If you stand up, the paint on your thighs will rub together and ruin everything!" Viki scolded. She hopped up and grabbed a fresh paper towel. "Hold still, Sophie. I've got it."

Viki knelt behind Sophie, reaching between her legs to catch the drip. She didn't just dab it; she slid the paper towel slowly up Sophie’s inner labia, trying not tovdisturb the fresh paint, her knuckles brushing against Robin’s hand as he held Sophie’s cheek open.

Sophie moaned, a sound that was half-frustration, half-pleasure. The combination of Viki wiping her sensitive entrance and Robin gripping her ass was too much. "Please... just let me close my legs!"

"No can do," Robin said, his voice straining. He was painfully aware that his crotch was hovering inches from Sophie’s upturned rear. Every time she squirmed, her ass brushed against his thigh. "The paint needs to dry. Viki, hurry up with the... drying."

"I'm going as fast as I can," Viki teased. She spent an inordinate amount of time smoothing the paper towel over Sophie’s entrance, ostensibly to ensure she was dry. "She's really producing a lot of moisture, Robin. It's practically pouring out of her."

"Stop talking about it!" Sophie shrieked, burying her face in her knees.

"It's a valid observation!" Viki defended

Robin's grip on her buttock tightening unintentionally. He watched as Viki finally pulled the paper towel away. "Okay. Crisis averted. But we need to seal the deal. I need to... redo the part you just messed up, and then connect the back to the front."

Robin moved his hand from Sophie’s hip to the crease of her thigh, his fingers sliding dangerously close to her sex again. He needed to blend the paint where the 'leg' of the shorts wrapped around to her groin. His finger was as hood a blanfing tool as any.

"Robin, wait," Sophie whimpered, feeling his fingers slide into the hot, wet space between her thighs.

"Just smoothing the transition," Robin whispered, his index finger brushing against her labia. He felt the slickness there and realized she was dripping again. "Oh, god. Sophie, you're... leaking again."

"I can't help it!" she cried. "You keep touching me!"

"You're touching her!" Viki accused, enjoying Robin's facial reactions this time. "You're practically fingering your own roomate, Robin!" She giggled, "Im not even mad, if anything im proud!"

"I am just blending!" Robin yelled back. "It's a technical application! But fine, brushes only... id preferbthat too"

He switched to a brush and moved the brush to the sensitive crease where her leg met her pelvis, right next to her lips. As he painted, Sofie shivered and squirmed, accidebtally grinding her clit against his knucle.

"AHHH!" Sophie screamed, her whole body convulsing. "RIGHT THERE! DON'T... DON'T STOP... I mean, STOP!"

Her legs buckled, and she would have fallen flat on her face if Robin hadn’t caught her. He wrapped his arm around her waist, pulling her back against him. His chest collided with her back, and his other hand, which was still covered in blue paint, slapped squarely onto her breast.

They stood there for a moment, frozen. Robin was holding her against him, one hand painted blue on her stomach, the other blue hand cupping her boob. Sophie was slumped back against him, panting, her legs trembling so hard she couldn't stand.

"Wow," Viki said, breaking the silence with a slow clap. "Now that is art."

Robin slowly peeled his hands off her, his face a mask of horror and lust. "I... I was just catching you."

"I know," Sophie breathed, her eyes glazed. She looked down at her chest, where a blue handprint now decorated her boob. "I think... I think we're done painting."

"Yeah," Robin agreed, stepping back and wiping his hands on his jeans, leaving blue streaks all over them. "Done. Definite... done."

"Good job, team," Viki grinned, standing up. "Sophie, you look... fantastic. Like a blue, naked goddess who just got manhandled by a smurf."

"Shut up, Viki," Sophie whispered, but she was smiling slightly. The embarrassment was overwhelming, but underneath it, she felt a strange, buzzing energy. She looked at Robin, who was refusing to make eye contact, staring determinedly at the floor. Hus jeans were tenting horribly. Sofie felt a pang of pity, mixing with her shame, "Thanks for the... help, Robin."

"Anytime," Robin croaked, more awkward and embarassed than Sofie, if that was possible. "It was all for... you know. Science."