a 1cm. diameter smooth bulge appears on the left side, at the base of penis, only detectable when erect. totally free of pain or any sensation, appears to be a bulge in the spongy tissue inside, not the skin. doesnt move around. same consistency as surrounding internal tissue. not red but normal skin colour. undetectable when flacid. no bending of penis and no interference with any functions. it doesnt extend down to testicles. i had chlamydia a year ago but cleared it up with doxycycline and re tested all clear. no more symptoms. no other problems at all.. barely visible but I can feel it.
It could be a Penile Cyst, which are harmless - or it simply may be as a result of the way in which your penis has developed.
The only specialist that would tell you for sure is a urologist - you need to weigh-up whether you have sufficient justification for your concern, and perhaps answer the question: is this a problem you need to get rectified?