The Doernbecher Children's Hospital in Portland provides an instructional guide to boys on how to tuck their genitals. The hospital – which bills itself as "Oregon's top ranked children’s hospital" – states, "Tucking can reduce any concerns you have about your body, how your clothes fit and how safe you feel in public."
The guidance from the "Gender Clinic" of the children's hospital states, "Tucking is moving the penis, testicles, or both out of the way. This makes the genital area look smoother and flatter."-- More...