Weight loss would be the most effective and safe way to accomplish this. Don't even think about taking testosterone. That will only make the problem worse over the long haul by causing testicular shrinkage. Don't smoke. Don't smoke. Don't smoke. That will harden the arteries to your privates. (and shorten your life by 15-20 years.) Avoid excessive alcohol intake. Otherwise, most of the advertised nostrums are absolutely worthless.
Done. Done. Done.