http://www.seankimerling.org/pages/self_exam/self_exam.html
The Sean Kimerling Testicular Cancer Foundation
The vast majority of testicular tumors are discovered by men themselves, either by accident or by performing the self-examination procedure. The testicular self-examination, or TSE, is a quick, simple, painless, exam that men can perform on themselves in the privacy of their own home. All men should perform the exam once a month. The exam takes only about three minutes to properly perform. By performing it regularly, you will become familiar with your anatomy and better able to recognize changes.