The penis as a source of identity and restlessness, legitimation for claims to dominance and fantasies of superiority, the object of fears of failure and loss: this small part of the body occupies a similarly highly dimensioned status in the physical and social self-image of men as does the brain. “Penissimo” traces this circumstance and its consequences for human culture with the help of six men with different linguistic and cultural backgrounds who try to investigate what role the penis plays as a key to the essence of masculinity.