I'm a 24 year old circumcised male. i recently noticed a small bump on the underside of the shaft of my penis, about halfway down. it is about the size of a bb, doesn't hurt or itch, seems attached to the skin above, and is easily moved around.

See in real life: Skin bumps can sometimes be diagnosed via video. A patient can try HealthTap PRIME for a virtual consult (there is a fee). Otherwise, one's primary care doctor or a dermatologist can examine the bump. It could be a closed comedone, a plugged sebaceous gland or follicle, an unusual mole, or less likely a wart. It may be best to get it examined, so that the doctor gets the texture and feel of it.