DAVID ARCHYMens Trunks Underwear Soft Breathable Rayon Made from Bamboo Trunk No Fly Pouch

My waistline hovers around 31" which really is very frustrating to buy for. should i risk the sm or the med?

How are these bamboo fiber (Rayon) compared to the micro modal?

What is the difference in pouches? ergonomic, u, enhanced u, 3d. i'm confused.

how durable is the material? and does it strech far?