Sans is a MONSTER and not a HUMAN, so he doesn't follow HUMAN biology like a HUMAN skeleton. Same with Gaster and Papyrus. 

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It was back to her normal job, ever since she had quit the Mafia, like she had promised Sans, and it was still somewhat hard not to be down about it. Matter of fact, Frisk was currently on her break, and she was sitting at one of the empty tables with none other than Chara, who had decided to visit a couple of days after that whole mission that they had gone on. "Someone seems a little bummed out. Come on, cheer up. You're acting like it's the end of the world." Chara teased towards the other human, who gave a small smile and she giggled a little, before sighing. 

"I know it's probably not a big deal. It's just... Call me crazy but... That job was kind of, I don't know? Fun?" Frisk shrugged. Okay, she knew it sounded weird when she said such a thing, because their job-- or what was her job, could be extremely dangerous, and could involve the death of other people. But it was the dangerous part that made it fun. The exhilarating experience that you felt whenever your life was on the line. Of course, she never planned to die, and even when she thought she was going to die, she had been terrified. But... It was hard to explain. 

"I get what you mean. But... Maybe it's best for you to get away from all of that now." Chara told her. "You have a family after all." She mentioned, which Frisk knew was true. Her family was extremely important to her, and she didn't want it to seem like she wasn't thinking about their feelings or how they might react if something awful happened to her. Sans had been pretty shook up when she had been stabbed, and she hated to see that look on his face when she woke up, seeing how scared he had been. She knew he must have been having a hard time without her. She never wanted to inflict that on him on purpose.

"Yeah but, you've got family. Toriel? Asriel?" Frisk pointed out. 

"W-Well, yeah... But... T-That's different. And Asriel isn't exactly family. He's my... best friend." Chara murmured, wanting to clear that up. That was the issue with her stupid newfound feelings. Well, they probably weren't that new. In fact, Chara wouldn't be surprised if she had always felt this way, with all the time that she'd spend with that goofball. But it was only recently that she discovered how she felt, and she was worried she might look like some kind of weirdo because others may have thought: isn't Asriel your brother? But that's not what it was. 

Frisk rose an eyebrow. "Hm? Your best friend?" She began to smile, which only made Chara confused as to what she was all of a sudden grinning about. "You seem to think quite highly of your best friend." She had teased, noticing how Chara had suddenly become embarrassed and she began to blush. Even more so when Frisk was teasing her, and she shook her head rapidly, while waving her arms in front of her as if to destroy her theory. 

"N-No! I m-mean, he's great but, I d-don't... Ugh..." Chara covered her face once again while Frisk laughed, knowing that Chara couldn't exactly lie to her. Having been someone who had had a big crush on Sans, Frisk knew a crush when she saw one. It made it so much easier to spot it from someone who wasn't very good at hiding it, likely because they had never had a crush before. "Just don't tell him... Or your boyfriend. Or just... Anyone." Chara whined, because she knew if Sans of all people knew, he would probably become extremely mischievous. Only because she had been so involved in his crush on Frisk, he might end up trying to do the same with her crush on Asriel, and she didn't need his advice. 

"I'm not sure if I'll have to do that for you." Frisk giggled once more, only to softly smile. "I think that's sweet, if you care that much about him. Why don't you just tell him?" And when Chara gave her a look as if to say: are you serious? She continued. "Okay... So, it's not easy to confess to someone but... It's better to do it than to just leave it. Could you imagine if I had never confessed to Sans?" Frisk wondered, only for Chara to roll her eyes at that. Yeah, if Frisk had never confessed, Sans probably would have never realised his own feelings for her. However, before it got to the point where their relationship would begin, he just shot her down and made her feel like shit until he was finally on the same level with her. Just because you were able to confess, didn't mean a relationship was likely to happen. And  besides... 

"I feel like it would make things weird." Chara admitted with a sigh, as she crossed her arms over her chest in thought, and she leaned back a little into her chair. In all the time that they had known each other, all the years of growing up in each other's presence, they had just been best friends, nothing more than that. And it felt pretty clear to Chara that Asriel was expecting them to end up with other people, especially with that conversation they had the other night. How she would find someone great, meaning he didn't think she had already found that person. 

Being someone who had helped Sans when he had feelings for Frisk, you would think she would know what to do when she had a crush of her own. However, that wasn't the case, whatsoever. In fact, she was pretty clueless on what she should do now that she was in the position of feeling like she cared about someone in that sort of way. It felt scarier and harder to deal with when it came to your own feelings, compared to helping someone else. It was like when you have your own personal issues, it's so much harder to sort that out, than to be there for another person and be their shoulder to cry on. You might give advice, but that doesn't mean you yourself would necessarily take it. 

"You realise he's totally into you too, right?" Frisk spoke up, earning a look from Chara that told her she wasn't convinced. "Come on... Not that I have ever seen Asriel in that way, but you can't deny that he is quite handsome, and he's a good person. The fact that he doesn't have a girlfriend yet actually shocks me." Frisk admitted. He could be pretty sweet, and he was extremely friendly. The fact that he didn't have more girls over him was unexpected to say the least, but that could mean because he had his eyes on one girl in particular. "So... I think he might have eyes for you. Why else would he spend so much time with you?" 

"I... Don't know." Chara shrugged. "Cause we're friends?" But even that didn't sound like a good enough reason. It was like Sans and Frisk - those two were practically inseparable, when neither of them were working and they were just at home together, when the kids were at kindergarten. They were a nice family, they cared about each other in such a way that it was utterly adorable. But would Asriel really care for a girl like herself, who kept saying how she didn't even feel like girlfriend material, and she kept insinuating she could never see herself being in a relationship? She was quite a plain girl, wasn't she? Why would he have any reason to pick her?

"I just think that if you keep feeling this way, eventually, you should talk to him about it. Even if he didn't feel the same way, I'm sure he'd be extremely supportive. It is Asriel after all." Frisk pointed out, until she glanced towards the wall that was behind the counter, where there was a clock hanging upon it. It was going to be the end of her lunch break soon, so she would have to start working again, but she hoped she had given Chara some things to think about. Actually, this conversation had cheered Frisk up a bit, and had for the moment in time taken her mind off of what she had been feeling sad about. Frisk smiled. "Anyway, I got to get back to working. Hope I've helped in some way." 

"Yeah... Thanks." Chara weakly smiled towards the other girl, before allowing her to start working once more. She sighed, staring down at her knees as she continued crossing her arms. Had eyes for her, huh...? Well... She had no reason to rush into anything. It hadn't been that long that she had discovered feeling this way, so she could wait for a bit, wait to see if she kept feeling this way, or maybe if she was able to notice any obvious sign that Asriel might return what she was feeling.

A huge part of her did hope that he felt the same.