Overview*
Penis comparison, quite literally, is the act of comparing the size of male genitalia. This can occur among males and also in scenarios involving futanari or a combination of males and futanari.
It could be seen as the equivalent tag to 'Boob Comparison' for females. However, there are fewer portrayals where size comparison occurs by concealing it in swimwear or similar clothing, unlike the female counterpart. As a result, R-18 posts dominate this tag.
The scenarios vary widely, ranging from heartwarming moments resembling playful interactions between young boys during bathing to humiliating play where an older person mocks the small size of the penis. There are also instances where muscular individuals simply compare their erections to showcase their virility. In essence, it can be seen as the almost opposite counterpart of female breast comparison ('Boob Comparison').
Moreover, there are variations that involve transitioning from a 'show-and-tell' approach to more direct forms of comparison.