The feeling of being "Peterbummed" is usually caused by a friend that either cock blocks, punches you in your "jewls", an erectile disfunction, a man named peter being bummed out, or a situation where you're just not spunky enough when the time to perform arises.
Nickname for someone named Peter a peterus is rarely found in the wild but when found he will outsmart you with his big brain. Commonly it's found that peteruses have really big dicks, but the one we found for this example. Has a very small liddle dick