I am a designer of seamless underwear. Seamless underwear is knitted, and knitting is the same principle as sweaters we usually wear now. The yarn arrangement is interrelated, so it is elastic and won't hurt very much. Compared with ordinary stitched woven underwear, woven fabrics are yarns arranged in warp and weft, but they are not elastic, which is equivalent to narrowing your stomach with a rope, and it is very uncomfortable to wear. Seamless is the power of weaving to shape you slowly and invisibly, which are two completely different principles. Persistence will definitely have an effect.