Oh My word!  These fit so well.  my waist is 38", but where I wear my pants and underwear is 34".  So I picked the US Medium size.  They fit just right.  The pouch holds well, lifting up and out, so nothing rubs or chaffs.  My wife says they really feel nice when we are in the bed.  Much better than the cotton brief or the cotton trunks I used to wear.