My boyfriend also has one that i have noticed but im not sure if there is more than one. It looks more or less like a freckel on his penis.
Sorry for the comments. Just reading threw what i said seems to be wrong. They are not lumps at all just looks like a black haze with defined edges you can tell where it begins and ends but not lump at all or any raised anything all normal just skin is dif color.
Sorry for spelling but let me confirm something. They are fadded not a solid dark black lump or ne thing looks like a bruse as i said ^