OuruikiaMen's Underwear Silky Smooth Boxer Briefs Long Leg Quick Dry Boxer Briefs with Separate Pouch

Q: Would too extra material for the sheath be uncomfortable?

I don't think you will find the extra material uncomfortable. However there are two things to consider - if you are not average to large size you may not like them because then you will find the extra unfilled material bothersome. In addition, it took a little while to adjust to the feeling of hanging more freely. You might also check out Separatec or David Archy double pouch boxer briefs.

Q: What size should I order with a 40ln waist

Dear Amazon Buyer, Many thanks for your inquiry. If you prefer loose fit, it is recommended you should buy size XL, if you perfer sung fit, you should buy size L. Thanks a lot. Ouruikia Customer Service Department Oscar