Any man who feels so inadequate about his penis size that he compensates for it by buying ridiculously large shit he doesn't need. This usually involves buying the biggest truck they can, raising it and putting airplane tires on it. Owning 20 or more large guns, talking about being violent or making threats when they are cowardice. And sleeping with big women to feel adequate, because they lack self esteem. They usually tend to hit, disrespect or yell at women. This may be because women won't/can't sit on their tiny dick. They also usually have a shit load of kids because they try to wear XL condoms, thus leading to unwanted kids whom they also beat and yell at.
Anyone with a unnecessary raised truck with huge tires, lots of guns, a huge 7 room house, or a reputation for lying about themselves in general, yet still doesn't have a goddamn woman. This can make them have small penis syndrome.