Some women feel very comfortable doing Breast Self-Exam (BSE) regularly (usually monthly after their period), which involves a systematic, step-by-step approach to examining the look and feel of one’s breasts. Other women are more comfortable simply feeling their breasts in a less systematic approach, such as while showering or getting dressed, or doing an occasional thorough exam.
The goal is to be able to report any breast changes to a doctor or nurse right away. Women who choose to use a step-by-step approach to BSE should have their BSE technique reviewed during their physical exam by a health professional.
By doing the exam regularly, you get to know how your breasts normally look and feel and you can more readily find any changes. If a change occurs, such as the development of a lump or swelling, skin irritation or dimpling, nipple pain or retraction (turning inward), redness or scaliness of the nipple or breast skin, or a discharge other than breast milk (which might be indicated by staining of your sheets or bra), you should see your healthcare professional as soon as possible for evaluation. Remember that most of the time, however, these breast changes are not cancer.
— Source: American Cancer Society