I've had a patient with similar "growths" that ended up being implants, actually. They were placed with the purpose of increasing friction during intercourse. Your photo appears similar to what his penis looked like.
Honestly doc I was petrified thinking about the worst for this patient. But Karma actually bites back. I had to refer him but after that it was discovered that he had involved in some unnatural sexual practice which led to broken penis and testicular rupture. Anyways Thank you for your answer.