Thong underwear, long popular with women as a solution to annoying panty lines, isn't just for females anymore. Some men have discovered the comfort of "barely there" underwear. A thong for a man must be cut differently in the front than the woman's version to accommodate a man's anatomy. Any soft, thin fabric will do for constructing the thong, but a soft cotton will result in the most comfortable garment.
Make a pattern. You can use a pair of bikini briefs as a guide. The front of the thong will be the same as the front of the bikini briefs. Although a woman's thong is a simple triangle, a man's thong must be fuller at the front to form a pouch. Cut two triangles of fabric, 2 inches on each side.
Measure from the base of the crotch to the top of the small of the back, then measure from the hip bone down the inside of the leg to the base of the crotch. Add these measurements together, and cut two pieces of elastic this long.
Starting at the top right of the front piece, pin the elastic to the sides of the front piece. Let the excess elastic hang free for now. Repeat on the other side. Sew the elastic in place.
Lay the excess lengths of elastic on top of each other, then stitch.
Measure around the hips, and cut a piece of elastic this length. Find the centre of this piece, and pin it to the centre top of the front piece of your thong. Pin the elastic along the top edge of the thong. You'll have excess elastic on each side. Sew the elastic in place.
Lay the two triangles of fabric on top of each other, with the wrong sides together and the point of the triangle facing down. Slip the free ends of the waist elastic between the triangles at the top on either side and pin. Slip the end of the doubled elastic between the triangles at the point and pin. Stitch around all three sides of the triangles to secure the elastic. Remove the pins, then use a zigzag stitch around all the edges of the triangle to help prevent fraying.
Use a zigzag stitch to sew the elastic. Sew both edges of the elastic for the most secure fit.