thank u for all the kind comments!! if you want to try yourself you just need snaps: https://www.minerva.com/mp/GBP/1/341120-M (or wherever you can find them), needle & thread, and some thrifted lace - ideally a thicker crocheted lace so that your stiches have something substantial to hold onto
sew two snaps halves onto each sleeve on the side of the lace you want to be facing the world (if you're a sewer it's the "right" side). then sew the complimentary halves of the snaps into the linings of your blazers. in terms of where they should be horizontally - they should both be near the inner arm hemline but on opposite sides of it. how "near" depends on the width of your lace pieces. in terms of where they should be vertically (ie how high up they should be) make sure to play around and measure beforehand how much you want the lace to stick out from the bottom.
you can also pin the lace on before sewing to get a feel and mark with tailor's chalk