I have a 32" waist and usually wear a size 30-31 in pants and jeans, and when it comes to underwear, I'm awkwardly in between a size S and M in most brands where the S is a little too snug to be comfortable, and the M is slightly too large and gets baggy over time. With Fahrenheit's Small, it fits pretty much perfect on me, fitting close to my skin while not being too tight or constricting, the pouch shape at the front helping greatly, and the elastic waist and leg bands stay put. I find the crotch is a bit slimmer than other men's briefs, but the snugness of the small helps keep everything contained. However, I find the Medium isn't that much larger than the Small, only being slightly looser all around. While the narrow crotch and looser legs mean being more prone to slippage down there, they still feel great under loose shorts, and I'm happy to keep the Mediums for hot and/or lazy days while the Smalls are better fitted and good to wear any time of the year.