hiii i saw your gender affirming pikachu surgery! i was wondering if you'd maybe go into a little bit of detail about how you did it? my wife has a pikachu she has had since she was a child and it has a rectangle tail, and i offered to change her tail but i haven't been able to find anyone else who had done something similar, until i saw your post that is <3 hope you are having a lovely day!!
ok i love explaining things so here's an extremely in depth tutorial that assumes you have never sewn before. if you do have sewing experience, then just skim it and look at the pictures to get the general idea. unfortunately i didn't take progress pics so we'll just have to look at my beautiful art instead.
(This tutorial assumes that your pikachu has a seam around all edges of the tail. If it's just a single flat piece of fabric, you can just straight up cut the heart shape instead. If one of the edges is just a fold instead of a seam, you will have to improvise and adapt.)
1. Trace your tail onto a piece of paper, and sketch out how you want the new heart shape to look. Keep it within the confines of the old tail.
2. Use a seam ripper (or a pair of scissors, small/precise ones if possible, very carefully) to cut out the stitches in the seam along the flat side of the tail that we are changing, as well as an inch or two down the adjacent two sides, like in the first part of the below image. You want to go as far as the curve shape will reach, plus an extra half inch or more.
*Sewing tip: You don't need to cut every individual stitch. Cut one stitch, skip a couple, then pull on a thread (using your seam ripper, tweezers, or your fingers), and the intervening stitches should all pull right out. Machine stitching uses two threads (one for each side of the fabric) that hook around each other in the middle of the seam, so if it's not working, try pulling on the other thread instead.
*Sewing tip: Try to leave longish bits of the original threads at the start and end of your modified section. (If you realize you cut them too short, then just pull the sides apart so it unravels some. Tada, now you have longer threads.) Tie the threads into a tight secure knot, so that the rest of the stitching won't start to unravel in the future. When it's time to sew, tuck these longish ends into the inside of the plushie so they aren't visible. (If you forget to tuck them inside, then just cut them short.) The below image shows the ends of the original thread tied off.
3. Unfold the seam allowance of the modified section, as in the second part of the above image. The rectangle I drew shows the original edge of the plushie — the section outside of that is the seam allowance. My plushie's fabric had a pretty visible crease line even after I unfolded it, but depending on material and construction, yours might not.
4. If you have a disappearing ink pen meant for sewing, or some other mark-maker that will be visible on the fabric but easy to wash out when you're done (such as pencil or washable marker), use it to draw the final heart shape onto the tail, like the third part of the above image. You can free hand it using your sketch as reference, or cut out your sketch and trace it onto the plushie. Remember to keep it within the original plushie outline! And if you can get it the same on both sides, it's helpful to draw the same line onto the reverse side of the tail.
*Sewing tip: Even if you think a marker is washable, it can still be a good idea to test it before drawing all over your plushie with it. Make a mark on the tail fabric within the now-exposed seam allowance, near the cut edge; wait 20 minutes (or however long you think the sewing will take you); then wash the mark off. If it washes out, you're good to use that marker. If it doesn't, oh well, at least the test mark is within the seam allowance so it won't be visible on the finished plushie.
*Sewing tip: If you don't have a suitable writing implement, you can skip this step; you'll just have to imagine that line while you work. Or you can use sewing pins or safety pins to pin your cut out heart shape sketch onto the plushie.
5. Cut your new seam allowance. You do NOT want to cut on the line you drew! Instead you are going to pick a seam allowance width — you can use the same width that the original plushie did or something else, I recommend about a centimeter for handsewing — and leave that much space between your drawn line and the edge you are cutting. In the fourth part of the image above, you can see that my new cut edge has the same silhouette as the drawn line, but is farther out. It's ok if this cut edge is a little messy, it won't show in the final plush.
*Sewing tip: Sewing sharp corners like the middle point of the heart can get weird (fabric bunching up, etc). You can minimize this weirdness by using a smaller seam allowance near the corner, or cutting a slit in the seam allowance at the corner. In the image above, you can see that my cut edge is a lot closer to the drawn line at the center of the point than it is in the rounded areas.
*Sewing tip: If you're nervous about messing it up, or you want the option to restore the plushie to its original shape later, you don't have to cut anything off. This just means a bulkier seam allowance, and the center of your heart's point might bunch up.
6. Thread your needle. I usually cut a length of thread as long as my arm, thread it through the needle, then tie the two ends together with a double knot, like in the first part of the below image. The final doubled-up thread is half as long as my original length.
*Sewing tip: A longer thread means you can sew more before you need to rethread your needle, but it also means more length flopping around that might get caught on something or tangled. If you're new to sewing, you might find a shorter thread easier to manage.
*Sewing tip: Before you start sewing, look at how the intact part of the plushie works. Notice how the seam allowance is folded in towards the middle? The second part of the image below shows how a fabric seam works: The "right" (nice) side of the fabric (drawn here in light yellow) is facing out, and the "wrong" side (drawn here in dark yellow) is facing in. The seam allowances are folded in so that the right sides are touching. The stitching is most visible on the wrong side of the fabric, inside the fold, where it's usually hidden inside the plushie. Between the two pieces of fabric, on the outside of the plushie, there is just a teeny tiny bit of thread visible. This is how sewers hide both the messy cut edge of the fabric and the majority of the stitching.
7. Starting where you tied off the original thread (or a couple stitches before, so the old stitches and the new stitches overlap for extra security), start sewing. Your sewing should follow the drawn-on heart line, and you will fold the seam allowance into the plush as you go, like in the third part of the above image. As you can see, folding the seam allowance into the plushie along the drawn line leaves your drawn line as the outside edge of the plushie like it's supposed to be. (And remember to tuck the long ends of the tied-off original thread into the inside of the plushie so they're not visible.)
*Sewing tip: You want to hold your needle inside the plushie to start, so your first time piercing the fabric brings the needle to the outside, and leaves the knot on the inside. This way the knot won't be visible on the finished plush. (If you mess this up, just make sure the knot is secure and then cut the ends of the thread very short to make them less visible)
*Sewing tip: If your knot pulls all the way through the fabric, then tie it into a triple or quadruple knot and try again. You just need the knot to be bigger than the natural holes in the fabric.
*Sewing tip: Refer to the second part of the above image to see the pattern that your stitches will follow. Push your needle into the right side of the fabric (along the drawn heart-shape line) and out of the wrong side. Move over a little bit, then go into the wrong side of the fabric and out of the right side, and immediately into the right side of the other piece of fabric and out of its wrong side. When you move the needle over, it will be inside the plushie, so you'll be doing it mostly by feel.
*Sewing tip: Most garments and plushies are constructed while inside out as much as possible — it's a little trickier sewing a seam on an otherwise complete, right-outside out plushie like this! It's normal for this to feel a little cramped, and for it to be hard to see what you're doing while your needle is inside the plushie. Don't worry if your stitches turn out a little wonky — as long as you are mostly following your drawn guideline, the plushie fabric will hide a lot of the wonkiness.
*Sewing tip: If you're having trouble with the stitch I described, you can instead try a stitch that goes through all four layers of fabric to the very outside of the plush, then over, then back through all four layers in the other direction. Or, go through all four layers, then loop back around to the top, then go through all four layers again in the same direction a little farther over from your first stitch, etc. Both of these stitches would be pretty visible on the finished plush, but they will hold it together, and give it some lovable hand-sewn charm.
*Sewing tip: If you really mess up, you can always cut and pull out your thread, and restart.
8. Continue sewing all the way along the heart shape edge of the plushie. The last half inch will be pretty difficult because it's hard to reach or see inside the now-very-small hole, but at least by now you know what you're doing — and this is why i recommended going half an inch past the end of the curve when you cut the original thread in step two, so that this tricky last bit of sewing is in a straight area, not a curve! If you end up needing to do some visible stitching in this area, I bet your pikachu won't mind. (And remember to tuck in the long ends of the tied-off original thread when you get there.)
9. Once your plushie is all sewn up, tie a double knot right up tight against the fabric.
*Sewing tip: If you want to, you can just cut the end short, but here's my method for hiding the ends entirely. Tie the knot, like in the first part of the below image. Then push your needle back into the seam right next to the knot, and back out of the fabric an inch or so way. (You don't want the needle to get lost inside the plushie, so make sure you're still holding onto the end until the tip gets pushed out, then pull on the tip to remove the needle.) Pull on the needle and bunch up the fabric so that the place the thread came out is physically close to the knot. Then cut the threads as short as you can. When you let go of the fabric, the ends will get pulled into the plushie.
Ta da, you're all done! And you can use the same techniques to mend or modify other plushies (along seam lines). Good luck and have fun!
edit: this post shows the ladder stitch that i used! though i never understand how these videos manage to pull the whole thing in one go afterwards, it does make the stitching easier but i have to pull it tight every 3-5 stitches or i’m gonna be struggling later. or at least i’d start tightening near the bottom then work my way up towards the needle, like tightening shoelaces.
