The general consensus among people with stretched ears is that uniquely shaped plugs and tunnels are safe to wear for short durations. As with any new earring, be wary of any discomfort. If you experience any discomfort you will need to remove the earrings as soon as possible. Uniquely shaped plugs should only be worn for daily use and never left in while you sleep. At the bare minimum, you should at least remove your shaped plugs or tunnels every other day to clean and oil your lobes and also check for any thinning.
Round plugs for stretched ear lobes evenly distribute pressure on all parts of a fistula, while non-round shapes place more pressure at points depending on the shape. Teardrop shaped plugs seem to report the least amount of issues, but can become uncomfortable if the fistula is higher on the ear, putting pressure on the cartilage. Shapes such as squares and triangles with sharper corners apply uneven distribution of pressure in the inner circumference of the ear, which can lead to weakening and thinning of the areas where the corners sit. To help reduce thinning, we suggest turning your square or triangle plugs so the corners do not always hit the same point on the inside of your fistula.
As with most all ear stretching inquiries, you will find someone's horror story about how using shaped plugs or tunnels ruined their day. That being said, these complications mainly happen when people wear shaped plugs for long durations, tried to stretch up with shaped plugs, wore them in lobes that were not fully healed, or had an allergic reaction to the material. People with allergic reactions to silicone have reported a more severe allergic reaction when wearing shaped plugs, which is more than likely attributed to the extra pressure caused by sharp corners or the uneven surface area of some shapes.
Shaped plugs are inserted the same way you would insert your circular plugs. They should never hurt going in or coming out; if they hurt you have the wrong size.
Teardrop: Teardrop shaped plugs do have a unique formula used to measure the size of the plug. You subtract the width of the plug from the length, divide by 2, and then add that number to the width. So for example, a teardrop plug that is 22mm long and 14mm wide would be considered an 18mm plug (22-14=8; 8/2=4; 4+14=18). While there is a formula to calculate "wear size" of teardrop plugs and tunnels, not every store or manufacture uses the same measurement scheme, so be wary when purchasing teardrop plugs. If your new teardrop plugs cannot be inserted without pain, then the size is incorrect.
Square Plugs: Square plugs sizes are generally reported as the length of the sides, so a 10mm plug would have 10mm side lengths. Please keep in mind that the diagonal of a square with 10mm length sides will be around 14mm. You can calculate the diagonal of other sizes by Google searching "hypotenuse calculator." Because the diagonal of the square will be longer than the advertized size of the plug, as well as the fact that the corner of square plugs are known to put extra pressure on the fistula, we suggest purchasing a smaller size square plug than your current size. Again, only wear plugs that can be inserted with no pain or discomfort; otherwise the size is incorrect.
Triangle Plugs: Generally the size reported for triangle plugs corresponds to the sides of the equilateral triangle; therefore, an 8mm triangle plug has three 8mm sides. When purchasing triangle shaped plugs, we suggest going with your same earring size, if your ears are pretty pliable, but if you have not been at your current size for a long period of time, you may want to consider purchasing a smaller size. Similar to the square plugs, the triangle plugs will put pressure on the fistula at the points of the triangle which are not located at your normal circular plug diameter, and therefore can cause pain if not sized correctly.
No, shaped plugs do not permanently distort the shape of the hole; however your fistula may not look as round as normal after wearing shaped plugs for a couple days immediately after taking them out.
We never suggest wearing shaped plugs for any extended period of time. Shaped plugs are known to cause thinning due to the uneven pressure put on the fistula. In extreme cases of thinning, circulation to the lobe can be damaged enough to even cause tears into the tissue without the wearer even being aware. So while some people have no issues with wearing shaped plugs for longer periods of time, we never suggest making it common practice.