The term "men's bikini" refers to a style of swimwear trunks similar to "speedos," a description borrowed from the Australian swimwear company Speedo that manufactures tight-fitting swim briefs. However, bikini briefs for men are slightly thinner on the sides than general briefs and are not specific for sports but instead for leisure activities such as sunbathing or swimming. A male bikini can also refer to a tightly-fitted swimsuit that extends with two suspender-like bands to cover over a portion of a man's chest, also known as a "mankini," as worn by comedian Sasha Baron Cohen in the 2006 film Borat.
Buy a men's bikini or briefs swimwear pattern from an online catalogue or at a fabric shop. It is possible to buy a briefs pattern and use synthetic fabric to make it into swimwear if more coverage is desired, or to modify the pattern to make it into a "mankini."
Buy swimwear fabric from a fabric shop or online. To ensure comfort and coverage with movement, use a synthetic swimwear fabric with a polymer base such as spandex or Lycra.
Take the swimsuit wearer's lower body measurements using a soft measuring tape, beginning with the crotch. For a comfortable fit, allow the measuring tape to drape loosely from back to front. Measure the waist and hips and circumference of each upper thigh, as directed by the swimwear pattern instructions.
Based on the measurements, cut out all of the pattern pieces. Lay the fabric on a flat surface and place the pattern pieces on the fabric, and pin. Cut out the fabric following the pattern.
Pin together the pieces of the male bikini. Try on the bikini carefully with the pins in place to see how the trunks fit. Using a mirror, make any modifications carefully with pins and folds to achieve the desired look.
Use a sewing machine to stitch together the pieces. Set the sewing machine to a swimwear stitch, such as an "elastic stretch stitch," which combines a narrow and wide zigzag pattern. This will ensure the seams "give" with fabric stretching.
Use swimwear liner to minimise transparency. To expand the swim trunks into a "mankini," also measure the distance from the hip over the shoulder to the upper buttocks and purchase approximately 1 metre (1 yard) of extra material to accommodate adding these braces-style triangles to the briefs.