[A/N: Overblown lead-in to physical fluff w/out an ending.

Last entry i said that some of these were going to be a "senses challenge" type thing. Ch1 was going to be taste, Ch2 was touch, Ch3 was sight; but i realized that wasn't quite right, so it's like this now: Ch1 is touch, Ch2 is thermal perception, Ch3 is sight, and this one Ch4 is "smell."

Which is another thing i'm really self-conscious about. I simply hate being perceived. But if i am, i better tf not smell bad.

I was raised with cats and dogs being the only form of physical affection that i got. That's why i keep writing like that oof.

TW/CW: scent/smell/olfactory descriptions and reactions, tracking, cuddling, bunting/rubbing, squishing/squashing/pressure contact, Zim has a nose/nostrils/olfactory sensors on his face]

Something was different. It wasn't clear what, or how it affected things, but something was definitely different.

Zim kept alert, on his toes, as he was always trained to do when something felt weird. His eyes dodged everywhere and he kept his antennae perked and twitchy. He even asked his computer if anything was off, including with it and his other robots, but it didn't find anything.

He kept his guard up, though. He made sure to pay attention everywhere he went, and only let his guard down some to relax in one of his labs where was never too preoccupied with one thing as to be vulnerable otherwise.

The feeling felt like it was creeping up on him again. He tensed in place, hoping that he could sneak up on it the same way that it was trying to sneak up on him. He got quiet…

But what he got wasn't something fishy. Dib knocked on the metal doorframe. He peeked his head inside and spoke in a quiet, concerned voice. "Are you doing alright, Space Boy???" Zim turned around and perked in the soft, usual way that he does when he was approached like this. "You seem kind of stressed out recently…"

"Euh…" He tapped his cheek. "Um… it's probably nothing, i guess."

"Are you sure??"

He waved his hand. "Yes yes, Zim is fine." He turned and spoke cheerily over his shoulder. "The Dib-monkey should not worry his huge, pretty head about me."

Dib huffed quietly. "Well, come up and relax with me whenever you want, alright?"

"Okay Dib-dear. Thank you for your concern." Dib stepped away back to whatever he was doing before the exchange.

Zim returned to his musings for only a few seconds before he was bludgeoned with that strange feeling again. His antennae perked upward and he looked all around him, certain that whatever it was was right on him and wouldn't be able to escape him this time.

But there wasn't anything visible there, because it wasn't something that existed that way. It was something that existed in a different way, but something still as real as…

Oh, that's what it must be. It was some kind of scent that had been plaguing his peace. But what he noticed about it is that it reached him far quicker and far stronger from the doorway than all throughout the rest of his base. He jumped at it.

He paused in the doorway to examine it. His feelers swayed to collect the chemicals that were there. He breathed in deeply a few times to pick it up through his nose as well. He was going to find what this was and where it was coming from so that he could…

Well, he wasn't too sure what he was going to do with it. It wasn't at all unpleasant, now that he actually thought about it. He couldn't quite place what it smelled like, but maybe finding the source would clear things up a little better.

Zim used his nose and his antennae to find it. His smell wasn't the best compared to his other senses, but he did his best. He followed it down the hallway, obviously going toward the stronger source compared to the other paths he found were there. No wonder he felt so disturbed by it.

He got up to the elevator. "Uhgf. If this is something that GIR brought into the house, then it could be anywhere by now!" He jumped in. "Compuuuteeer!!! Take me to the three most recent floors that the elevator stopped at."

"Processing." At some point, Zim had considered changing the voice to something that sounded less… 'disapproving:' or at least a little less touchy about him being stupid sometimes. But it was just a fleeting thought, he supposed.

Now that he was standing still, he could study the smell a little better. Above the presence of his housemates, he felt how weird and chemical it was despite being pleasant. He hadn't yet experienced anything quite like it, at least not so up-close. He knew things like Earthen plants, which smelled alright to him, but those were natural scents. The artificial stuff, like the foods and perfumes that people wore were usually too aggressive and disgusting for him.

This wasn't like that. It was artificial for sure, and overbearing in an acceptable way. There was something about it that made his insides feel strange. If he had hair, it would be standing partway on end. If he had to describe it, he'd call it "blue." Blue like the Suck Munkeys that GIR would sometimes get, or like if the logo on the back of Dib's computer were a little darker. But it wasn't quite as 'cold' as the drink, or exactly 'noisy' like the computer.

The elevator stopped at one of the floors. Zim stepped out and took a moment to see if he could smell it there. When he determined that he couldn't sense it, he stepped back inside and did the same with the other floor. The last stop was the main floor. The door opened up and Zim saw his best friends.

"Oh, hey." They locked eyes. "I was thinking about going to the store." Dib was holding a shopping list in his hand. "Do you wanna come with??"

Zim cocked his head as if he were listening, but he was still too concentrated on the scent to hear what was said. The aroma was strong here, so it had to be somewhere in the main house. He followed it to the counter with the paper, but it was coming from somewhere else besides that.

"Did you want me to write something down?" He turned his head again and picked it up from where Dib and GIR were. He scurried to the far side of the table.

They watched him. "What's he doin'?" Zim stepped a bit closer, his antennae going wild in every direction.

He dodged and ducked to get a better location. "S-smell," he muttered. "There's a smell."

"I DIDN'T HAVE ONION RINGS!"

Zim paused and looked at GIR. He was thankful that he couldn't pick that up. "No! No, it smells new."

"Oh. It's Dib!!" He pointed.

"Um, yeah probably." He scratched the back of his neck. "I had to get a different soap because they didn't have the one that i usually get at the store."

Zim's antennae were attentive and facing forward as he crept up to Dib. He eyed him for a moment and got close enough to him to tap his chest with the tips of his sensillum. He breathed in deeply, and sure enough, this was the strongest place that he sensed the smell.

Dib shrunk back a few inches. "Uummm…" He dodged his eyes. "Do you not like it?? I was going to see if they had my regular one right now."

Zim opened his eyes and blinked a couple more times. He looked blankly at Dib's anxious face. "What's the name of your regular one?"

"Iiitt's caaalled…" he squinted at the list, but Zim raised his arm to snatch it away from him.

"GIR will get it for you." He reached to hand it to the little robot. "Take care of this, and take your time."

GIR blinked mindlessly and took up the paper. He glanced it over, then gobbled it into his mouth. He stood up on the couch and saluted with red eyes before hopping down and skipping out the door.

They followed him with their eyes. "Okaayy…" Dib glanced at Zim's smirk. "I was gonna get lunch too, but…"

"I'll text him in a few." He smiled, then grinned. "In the meantime…" He kissed his antennae tips all over Dib's face; "let me smell the pretty Dib-flower."

Dib pulled his head back and shook off the little tickles with a grin, but wasn't ready to be pushed onto the couch the way that he was. "Oof…" He also wasn't expecting for Zim to pounce on him, but he pinched his eyes closed in anticipation.

He didn't land with his knees in Dib's gut how he liked to. Instead, Zim aimed himself to land and support on the couch itself. He nuzzled his face against Dib's jaw and settled his body against his mate's. He sniffed up and down Dib's neck to breathe in the new aroma that was playing with the natural scent he knew and loved. His feelers flopped forward again and dusted across Dib's face, which made him smile.

Zim latched his claws onto Dib's clothes and pulled his wrists upwards. He smothered his face to his chest and rubbed against him, audibly breathing in all of his scent. He pushed his hips up and tilted his head down to press his forehead against Dib's breastplate.

Dib grinned at the silly display. He shifted himself to get comfortable and lifted his arms to wrap around his darling, holding him close with one and brushing his hand against Zim's skin with the other. "So you don't like it???"

Zim kept sniffing Dib's chest and belly for a few more moments, but shuffled his antennae up and down his face and neck to show that he was thinking about his answer. He pushed further against his lover and rubbed his face side to side as he slid up his body. He tilted his head to have his chin in the center of his chest and looked up with big cute eyes before smirking. "I hate it."

They both giggled, and Zim moved his face up to Dib's neck to rub against that for a little bit. He stuck the tips of his sensillum into Dib's hair, and he wriggled his body and arms against his perch. Dib squeezed the little guy tightly in his arms and with his big head, and Zim made a happy, squeaky chirp under the pressure. To break free, he pushed against him enough to twist his body so that he squashed Dib into the couch with his shoulder and his hip as he flipped to be a little spoon.

Zim closed his eyes and craned backwards over his pak to cuddled his head against Dib's neck from this new angle, and rubbed his arms against his restraints. "You're so weird!!" Dib laughed.

"Shush shush shush." Zim brought his palms up to Dib's cheeks and he smushed them in little circles against his teeth. He giggled and shook his head away from the tiny hands, but tilted his neck to kiss Zim on the top of his head. He relaxed near it again, and Zim brushed his claws through Dib's hair and against his scalp for a few minutes. When his arms got tired, he pulled them back over top of Dib's, slipping his fingers between his mates and holding on lovingly.

Zim didn't really want to move, but his neck was starting to get sore from the strange angle. He pulled his knees up and planted his boots on Dib's legs to push his hips up. "Hey!" He pivoted and scooted so that he could sit on the couch next to Dib, but he moved his arm with him to stay wrapped up. He sighed onto his shoulder happily, and softly bunted his nose to Dib's jaw. He hummed with appreciation, and giggled out loud when Zim flicked his tongue under his chin a couple times. "You creep!"

Zim touched a finger from between Dib's to his mouth for a moment. "Shh shh…" He relaxed again, and very gently brought his lips to passionately kiss Dib's neck. He breathed out against his skin. "I love my Dib-smelly."

Dib blushed and squeezed Zim tightly again. "Dib loves Zim, too."