The tittymuscles, the bust brothers, the dancers that are the stars of the flexrumba
Increased by: Dumbbell Chestflies, Bench Press, Pushups,
In its full name known as Gynecomastia. It is a running meme on /fit/ that anyone with big or at least considerably bigger pecks than their abs, have gyno. Which is an enlarged area near the nipples, as the tissue there have been set to growth due to hormonal inbalance.
Not to be confused with lipomastia, when it is just fucking fat on your tiddies and happens due to being a fat fuck.