When somebody acts completely dildonic for a long time possibly months or years. There entire existence is swallowed up and any link to the human race has been lost. nobody wants to know them and they rarely have friends. if they do engage in some form of social activity you can pretty much guarantee it will be with other dildonians who have also been rejected from society.
Q) whos that cocksucker sniffing round my ex missus?
A) dont worry about him mate he's a fucking dildonian! he poses no threat to anyone.
A male, obsessed with the size of his penis and his overabundance of testosterone, who shouts at anyone willing to listen to him about his excess of sexual potency.
A guy going onto a forum and shouting " HEY EVERYONE! I GOT A 15 INCH COCK!" would be a dildoni.