From Fehr Trade:
These leggings are specifically designed for active men, with a roomy front pouch, rear panel with optional zippered pocket, and elasticated waistband. The one-piece leg has no side seams to interrupt a crazy print, and your choice of biker short or full length means they can be worn all year round, even as base layers or underwear.
Beginner sewing skills are required for the basic shorts or leggings - some experience with sewing knits is expected. Intermediate sewing skills are required for the zipper pocket.
Note that this pattern requires stretch jersey fabric with good recovery - it is drafted with negative ease and intended to be very close fitting. The biker short hem ends 8 cm (3 in) above the knee.