Okay so I found a few people drawing this headcanon on Tumblr and I think it's pretty neat so I wrote for it

This is also extremely self-indulgent and kiiiinda self-projecting (just about gender stuff in general, I'm not transfem), but like that's half of my work anyways

This one isn't very well-written because I kind of just wrote it in like a half hour at most but I'm currently happy with it even though I'm probably gonna hate it in a month or so. I'm also kind of nervous to publish this because I'm not sure what people are gonna think of something like this lol

Plot summary: Fan is anxious about coming out as trans to her girlfriend, Test Tube.

---

 Fan was sprawled out on her bed and staring at the orange ceiling, fixated on the sunlight filtering through the shades on the window. Her thoughts were racing, and no matter now many times she tried to reassure herself she was worried over nothing, her mind would always come back at her with a "but what if...?" 

 She sat upright, pondering on the events of the last few weeks or so. It was a very contemplative time, and she had figured out quite a bit about herself. For one thing, she was a girl- or at least, she was pretty sure she was a girl. It wasn't 100%, but at this point, being a girl sounded more correct to her than being a boy, which she had believed she was for most of her life. Fan had always sort of felt like a girl, but it didn't fully click until recently that she might not be cis. The only person who knew so far was Lightbulb, whom Fan confided in because she was also a trans girl. Fan wasn't quite sure how she would feel yet about being out to everyone else, but there was one person she definitely was nervous to tell: Test Tube.

 Back before the two of them started dating, it might have been a bit different, but since they were more than just best friends now, Test Tube's feelings on the matter worried Fan. She had no idea if Test Tube liked girls, and even if she did, Fan had no idea if she would want to date a trans girl. What if Test Tube just became uncomfortable with Fan altogether? What if they stopped being friends? What if they never spoke again?!

 Fan mentally slapped herself. "Lightbulb and Paintbrush are both trans, and Test Tube has no problem with it, stupid! Why would it be any different for you?" she thought aloud. (She had a habit of talking to herself.) It just WOULD BE!! her brain responded. She took a deep breath. "Okay, so, maybe she wouldn't stop being your friend, but still! What if she wants to break up?" she said to herself. If Test Tube wanted to end the relationship, she would have every right to do so, since Fan wasn't entitled to her, but also, there was the glaring issue that Fan kind of did not want that to happen.

 Fan readjusted, because her legs were starting to fall asleep. "Everything's gonna be okay," she said. "You're gonna have to tell her eventually, and when you do, it can't go that badly." Before she could think too much longer, someone knocked on the door. Fan knew it wouldn't be Paintbrush, since they would have just used the card and come in. She got up and looked through the peephole to see who it was.

Test Tube. Of course.

 Great. Now of all times. Fan opened the door, looking at Test Tube nervously. "Hey, babe! Uh... Paintbrush isn't here, right?" asked Test Tube. Fan gulped. "Uh, nope! It's just me! By myself. Here. In my hotel room," she replied. Way to sound natural. "Wanna come in?" Fan asked before she could make things more awkward, and Test Tube obliged, greeting Fan with the usual kiss on the cheek.

 The two of them sat down on Fan's bed. Test Tube cleared her throat. "Uh, I might as well get straight to the point..." she said, looking at Fan. "Forgive me if I'm reading too hard into things, but, uh, have you been... okay recently? For the past week or so, you've seemed kind of like something's off." Fan shuddered. Test Tube would likely see through her if she tried to lie, but she figured it was worth a shot anyways, and began stammering a bit. 

 "Uh- pfft! No, everything's fine! There's- there's nothing you need to worry about!" she replied, fidgeting with her hands. As Fan expected, Test Tube didn't seem convinced. Fan grew a bit frustrated with herself. She wasn't one to lie about how she was feeling, so of course Test Tube would notice her acting different.

 Test Tube took Fan's hand. "Okay, um... you're sure, right? You can tell me if something's wrong," she assured Fan. Fan stared nervously into her girlfriend's eyes. She didn't like hiding things from Test Tube. Maybe she could just kind of address her problem without revealing what it was actually about? She swallowed hard. "Well, there kind of is something wrong, but the thing is, I... I want to tell you! Really bad! But I'm... I'm scared to," Fan confessed. Test Tube seemed a little bit surprised. "What are you scared of?" she asked.

 Fan nervously fidgeted with one of the paper points on top of her head. "I guess I'm scared that you... won't like me anymore? Like, not cuz I did anything, or something like that, just... I don't think that you'll view me in the same way," Fan replied, looking down at the floor. The glass object's demeanor seemed increasingly worried. "Fan, we've been best friends for years, and you're my boyfriend! I wouldn't just stop liking you!" Fan cringed a little bit at the word "boyfriend", although she knew Test Tube wasn't intentionally misgendering her. 

 "Well, at the very least, you might not want to date me anymore, and I like you too much, and I don't wanna break up with you!" Fan continued, turning to the side and gripping at her wooden sides as she grew more and more tense. Test Tube put a light hand on Fan's shoulder, rubbing her thumb on her arm in an attempt to somewhat calm her down. "I don't understand, though. Why would that happen?" she asked anxiously. Fan curled her legs up towards her, and threw her hands out in an exaggerated fashion. "Because I don't even know if you like girls!!" she lamented somewhat loudly. A second or two later, her stomach dropped as she realized what she had just said.

 Fan looked up at Test Tube, who looked back at her in confusion. Fan's mind was going a mile a minute. OH, great job, Fan! You really screwed yourself over now! A few horribly tense seconds passed before Test Tube finally said something. "I- I'm sorry, what is going on, exactly?" she asked, trying to make sense of what was going on in her head. Fan turned back to face her girlfriend, feeling her heart beating louder and faster. Welp, you can't make it any worse, she thought. Might as well just get this over with. 

 Fan let out a heavy sigh. "I... I'm about 95% sure that I'm trans. I figured it out about a week or two ago, and I was worried it would affect our relationship. That's why I was so anxious around you all this time," she confessed. Test Tube mouthed "oh", then thought for a second. "You're... a trans woman?" she asked. Fan nodded in response. "Well, golly..." said Test Tube absent-mindedly.

 She sighed, placing her hands on Fan's sides. "Fan, it doesn't matter to me if you're trans or cis, or what gender you are. I love you because you're you. If I had known you as a girl from the very beginning, it wouldn't have changed anything," she said to the smaller object. "Also, I guess to simplify and answer your concerns, yes, I do like girls, so, in terms of our romantic relationship, we're good."

 Fan had to take a second to process what she was hearing, because she could hardly believe it. (Granted, she definitely should have predicted this outcome, but hey.) Everything actually went okay. Test Tube still loved her, and that wasn't going to change. 

She smiled, tearing up, and gave Test Tube a tight hug, which was returned. "Thank you, Testy. That means a lot to me," she said. Test Tube nodded. "Anything," she replied. "I'm so lucky you're my girlfriend." The two pulled away, and shared a quick kiss. "I love you," said Fan, gazing into Test Tube's eyes. Test Tube gave her a warm smile.

 "I love you too."